description: Some number of people (this number is even) have stood in a circle. The people stand in the circle evenly. They are numbered clockwise starting from a person with the number 1. Each person is looking through the circle's center at the opposite person.
  
  <image> A sample of a circle of 6 persons. The orange arrows indicate who is looking at whom.
  
  You don't know the exact number of people standing in the circle (but this number is even, no doubt). It is known that the person with the number a is looking at the person with the number b (and vice versa, of course). What is the number associated with a person being looked at by the person with the number c? If, for the specified a, b, and c, no such circle exists, output -1.
  
  Input
  
  The first line contains one integer t (1 ≤ t ≤ 10^4) — the number of test cases. Then t test cases follow.
  
  Each test case consists of one line containing three distinct integers a, b, c (1 ≤ a,b,c ≤ 10^8).
  
  Output
  
  For each test case output in a separate line a single integer d — the number of the person being looked at by the person with the number c in a circle such that the person with the number a is looking at the person with the number b. If there are multiple solutions, print any of them. Output -1 if there's no circle meeting the given conditions.
  
  Example
  
  Input
  
  
  7
  6 2 4
  2 3 1
  2 4 10
  5 3 4
  1 3 2
  2 5 4
  4 3 2
  
  
  Output
  
  
  8
  -1
  -1
  -1
  4
  1
  -1
  
  Note
  
  In the first test case, there's a desired circle of 8 people. The person with the number 6 will look at the person with the number 2 and the person with the number 8 will look at the person with the number 4.
  
  In the second test case, there's no circle meeting the conditions. If the person with the number 2 is looking at the person with the number 3, the circle consists of 2 people because these persons are neighbors. But, in this case, they must have the numbers 1 and 2, but it doesn't meet the problem's conditions.
  
  In the third test case, the only circle with the persons with the numbers 2 and 4 looking at each other consists of 4 people. Therefore, the person with the number 10 doesn't occur in the circle.
solution: import static java.lang.Math.max;
  import static java.lang.Math.min;
  import static java.lang.Math.abs;
  import java.util.*;
  import java.io.*;
  import java.math.*;
  
  /**
   *
   * @Har_Har_Mahadev
   */
  
  /**
   * Main , Solution , Remove Public
   */
  public class B {
  
  	public static void process() throws IOException {
  
  		long a = sc.nextLong(),b = sc.nextLong(),c = sc.nextLong();
  		long min = min(a, b),max = max(a, b);
  		long values = max-min-1;
  		long have = min-1 + max(0,c-max);
  		if(values < have) {
  			System.out.println(-1);
  			return;
  		}
  		long n = (max-min)*2;
  		long next = c + n/2;
  		if(next > n) {
  			next-=n;
  		}
  		
  		System.out.println(next);
  
  	}
  
  	//=============================================================================
  	//--------------------------The End---------------------------------
  	//=============================================================================
  	private static long INF = 2000000000000000000L, M = 1000000007, MM = 998244353;
  	private static int N = 0;
  
  	private static void google(int tt) {
  		System.out.print("Case #" + (tt) + ": ");
  	}
  
  	static FastScanner sc;
  	static FastWriter out;
  
  	public static void main(String[] args) throws IOException {
  		boolean oj = true;
  		if (oj) {
  			sc = new FastScanner();
  			out = new FastWriter(System.out);
  		} else {
  			sc = new FastScanner("input.txt");
  			out = new FastWriter("output.txt");
  		}
  		long s = System.currentTimeMillis();
  		int t = 1;
  		t = sc.nextInt();
  		int TTT = 1;
  		while (t-- > 0) {
  			//			google(TTT++);
  			process();
  		}
  		out.flush();
  		//		tr(System.currentTimeMillis()-s+"ms");
  	}
  
  	private static boolean oj = System.getProperty("ONLINE_JUDGE") != null;
  
  	private static void tr(Object... o) {
  		if (!oj)
  			System.err.println(Arrays.deepToString(o));
  	}
  
  	static class Pair implements Comparable<Pair> {
  		int x, y;
  
  		Pair(int x, int y) {
  			this.x = x;
  			this.y = y;
  		}
  
  		@Override
  		public int compareTo(Pair o) {
  			return Integer.compare(this.x, o.x);
  		}
  
  		/*
  		 	@Override
  		    public boolean equals(Object o) {
  		        if (this == o) return true;
  		        if (!(o instanceof Pair)) return false;
  		        Pair key = (Pair) o;
  		        return x == key.x && y == key.y;
  		    }
  		 
  		    @Override
  		    public int hashCode() {
  		        int result = x;
  		        result = 31 * result + y;
  		        return result;
  		    }
  		*/
  	}
  
  	/////////////////////////////////////////////////////////////////////////////////////////////////////////
  
  	static int ceil(int x, int y) {
  		return (x % y == 0 ? x / y : (x / y + 1));
  	}
  
  	static long ceil(long x, long y) {
  		return (x % y == 0 ? x / y : (x / y + 1));
  	}
  
  	static long sqrt(long z) {
  		long sqz = (long) Math.sqrt(z);
  		while (sqz * 1L * sqz < z) {
  			sqz++;
  		}
  		while (sqz * 1L * sqz > z) {
  			sqz--;
  		}
  		return sqz;
  	}
  
  	static int log2(int N) {
  		int result = (int) (Math.log(N) / Math.log(2));
  		return result;
  	}
  
  	public static long gcd(long a, long b) {
  		if (a > b)
  			a = (a + b) - (b = a);
  		if (a == 0L)
  			return b;
  		return gcd(b % a, a);
  	}
  
  	public static long lcm(long a, long b) {
  		return (a * b) / gcd(a, b);
  	}
  
  	public static int lower_bound(int[] arr, int x) {
  		int low = 0, high = arr.length - 1, mid = -1;
  		int ans = -1;
  		while (low <= high) {
  			mid = (low + high) / 2;
  
  			if (arr[mid] > x) {
  				high = mid - 1;
  			} else {
  				ans = mid;
  				low = mid + 1;
  			}
  		}
  
  		return ans;
  	}
  
  	public static int upper_bound(int[] arr, int x) {
  		int low = 0, high = arr.length - 1, mid = -1;
  		int ans = arr.length;
  		while (low < high) {
  			mid = (low + high) / 2;
  
  			if (arr[mid] >= x) {
  				ans = mid;
  				high = mid - 1;
  			} else {
  				low = mid + 1;
  			}
  		}
  
  		return ans;
  	}
  
  	static void ruffleSort(int[] a) {
  		Random get = new Random();
  		for (int i = 0; i < a.length; i++) {
  			int r = get.nextInt(a.length);
  			int temp = a[i];
  			a[i] = a[r];
  			a[r] = temp;
  		}
  		Arrays.sort(a);
  	}
  
  	static void ruffleSort(long[] a) {
  		Random get = new Random();
  		for (int i = 0; i < a.length; i++) {
  			int r = get.nextInt(a.length);
  			long temp = a[i];
  			a[i] = a[r];
  			a[r] = temp;
  		}
  		Arrays.sort(a);
  	}
  
  	static void reverseArray(int[] a) {
  		int n = a.length;
  		int arr[] = new int[n];
  		for (int i = 0; i < n; i++)
  			arr[i] = a[n - i - 1];
  		for (int i = 0; i < n; i++)
  			a[i] = arr[i];
  	}
  
  	static void reverseArray(long[] a) {
  		int n = a.length;
  		long arr[] = new long[n];
  		for (int i = 0; i < n; i++)
  			arr[i] = a[n - i - 1];
  		for (int i = 0; i < n; i++)
  			a[i] = arr[i];
  	}
  
  	//custom multiset (replace with HashMap if needed)
  	public static void push(TreeMap<Integer, Integer> map, int k, int v) {
  		//map[k] += v;
  		if (!map.containsKey(k))
  			map.put(k, v);
  		else
  			map.put(k, map.get(k) + v);
  	}
  
  	public static void pull(TreeMap<Integer, Integer> map, int k, int v) {
  		//assumes map[k] >= v
  		//map[k] -= v
  		int lol = map.get(k);
  		if (lol == v)
  			map.remove(k);
  		else
  			map.put(k, lol - v);
  	}
  
  	// compress Big value to Time Limit
  	public static int[] compress(int[] arr) {
  		ArrayList<Integer> ls = new ArrayList<Integer>();
  		for (int x : arr)
  			ls.add(x);
  		Collections.sort(ls);
  		HashMap<Integer, Integer> map = new HashMap<Integer, Integer>();
  		int boof = 1; //min value
  		for (int x : ls)
  			if (!map.containsKey(x))
  				map.put(x, boof++);
  		int[] brr = new int[arr.length];
  		for (int i = 0; i < arr.length; i++)
  			brr[i] = map.get(arr[i]);
  		return brr;
  	}
  
  	// Fast Writer 
  
  	public static class FastWriter {
  		private static final int BUF_SIZE = 1 << 13;
  		private final byte[] buf = new byte[BUF_SIZE];
  		private final OutputStream out;
  		private int ptr = 0;
  
  		private FastWriter() {
  			out = null;
  		}
  
  		public FastWriter(OutputStream os) {
  			this.out = os;
  		}
  
  		public FastWriter(String path) {
  			try {
  				this.out = new FileOutputStream(path);
  			} catch (FileNotFoundException e) {
  				throw new RuntimeException("FastWriter");
  			}
  		}
  
  		public FastWriter write(byte b) {
  			buf[ptr++] = b;
  			if (ptr == BUF_SIZE)
  				innerflush();
  			return this;
  		}
  
  		public FastWriter write(char c) {
  			return write((byte) c);
  		}
  
  		public FastWriter write(char[] s) {
  			for (char c : s) {
  				buf[ptr++] = (byte) c;
  				if (ptr == BUF_SIZE)
  					innerflush();
  			}
  			return this;
  		}
  
  		public FastWriter write(String s) {
  			s.chars().forEach(c -> {
  				buf[ptr++] = (byte) c;
  				if (ptr == BUF_SIZE)
  					innerflush();
  			});
  			return this;
  		}
  
  		private static int countDigits(int l) {
  			if (l >= 1000000000)
  				return 10;
  			if (l >= 100000000)
  				return 9;
  			if (l >= 10000000)
  				return 8;
  			if (l >= 1000000)
  				return 7;
  			if (l >= 100000)
  				return 6;
  			if (l >= 10000)
  				return 5;
  			if (l >= 1000)
  				return 4;
  			if (l >= 100)
  				return 3;
  			if (l >= 10)
  				return 2;
  			return 1;
  		}
  
  		public FastWriter write(int x) {
  			if (x == Integer.MIN_VALUE) {
  				return write((long) x);
  			}
  			if (ptr + 12 >= BUF_SIZE)
  				innerflush();
  			if (x < 0) {
  				write((byte) '-');
  				x = -x;
  			}
  			int d = countDigits(x);
  			for (int i = ptr + d - 1; i >= ptr; i--) {
  				buf[i] = (byte) ('0' + x % 10);
  				x /= 10;
  			}
  			ptr += d;
  			return this;
  		}
  
  		private static int countDigits(long l) {
  			if (l >= 1000000000000000000L)
  				return 19;
  			if (l >= 100000000000000000L)
  				return 18;
  			if (l >= 10000000000000000L)
  				return 17;
  			if (l >= 1000000000000000L)
  				return 16;
  			if (l >= 100000000000000L)
  				return 15;
  			if (l >= 10000000000000L)
  				return 14;
  			if (l >= 1000000000000L)
  				return 13;
  			if (l >= 100000000000L)
  				return 12;
  			if (l >= 10000000000L)
  				return 11;
  			if (l >= 1000000000L)
  				return 10;
  			if (l >= 100000000L)
  				return 9;
  			if (l >= 10000000L)
  				return 8;
  			if (l >= 1000000L)
  				return 7;
  			if (l >= 100000L)
  				return 6;
  			if (l >= 10000L)
  				return 5;
  			if (l >= 1000L)
  				return 4;
  			if (l >= 100L)
  				return 3;
  			if (l >= 10L)
  				return 2;
  			return 1;
  		}
  
  		public FastWriter write(long x) {
  			if (x == Long.MIN_VALUE) {
  				return write("" + x);
  			}
  			if (ptr + 21 >= BUF_SIZE)
  				innerflush();
  			if (x < 0) {
  				write((byte) '-');
  				x = -x;
  			}
  			int d = countDigits(x);
  			for (int i = ptr + d - 1; i >= ptr; i--) {
  				buf[i] = (byte) ('0' + x % 10);
  				x /= 10;
  			}
  			ptr += d;
  			return this;
  		}
  
  		public FastWriter write(double x, int precision) {
  			if (x < 0) {
  				write('-');
  				x = -x;
  			}
  			x += Math.pow(10, -precision) / 2;
  			//		if(x < 0){ x = 0; }
  			write((long) x).write(".");
  			x -= (long) x;
  			for (int i = 0; i < precision; i++) {
  				x *= 10;
  				write((char) ('0' + (int) x));
  				x -= (int) x;
  			}
  			return this;
  		}
  
  		public FastWriter writeln(char c) {
  			return write(c).writeln();
  		}
  
  		public FastWriter writeln(int x) {
  			return write(x).writeln();
  		}
  
  		public FastWriter writeln(long x) {
  			return write(x).writeln();
  		}
  
  		public FastWriter writeln(double x, int precision) {
  			return write(x, precision).writeln();
  		}
  
  		public FastWriter write(int... xs) {
  			boolean first = true;
  			for (int x : xs) {
  				if (!first)
  					write(' ');
  				first = false;
  				write(x);
  			}
  			return this;
  		}
  
  		public FastWriter write(long... xs) {
  			boolean first = true;
  			for (long x : xs) {
  				if (!first)
  					write(' ');
  				first = false;
  				write(x);
  			}
  			return this;
  		}
  
  		public FastWriter writeln() {
  			return write((byte) '\n');
  		}
  
  		public FastWriter writeln(int... xs) {
  			return write(xs).writeln();
  		}
  
  		public FastWriter writeln(long... xs) {
  			return write(xs).writeln();
  		}
  
  		public FastWriter writeln(char[] line) {
  			return write(line).writeln();
  		}
  
  		public FastWriter writeln(char[]... map) {
  			for (char[] line : map)
  				write(line).writeln();
  			return this;
  		}
  
  		public FastWriter writeln(String s) {
  			return write(s).writeln();
  		}
  
  		private void innerflush() {
  			try {
  				out.write(buf, 0, ptr);
  				ptr = 0;
  			} catch (IOException e) {
  				throw new RuntimeException("innerflush");
  			}
  		}
  
  		public void flush() {
  			innerflush();
  			try {
  				out.flush();
  			} catch (IOException e) {
  				throw new RuntimeException("flush");
  			}
  		}
  
  		public FastWriter print(byte b) {
  			return write(b);
  		}
  
  		public FastWriter print(char c) {
  			return write(c);
  		}
  
  		public FastWriter print(char[] s) {
  			return write(s);
  		}
  
  		public FastWriter print(String s) {
  			return write(s);
  		}
  
  		public FastWriter print(int x) {
  			return write(x);
  		}
  
  		public FastWriter print(long x) {
  			return write(x);
  		}
  
  		public FastWriter print(double x, int precision) {
  			return write(x, precision);
  		}
  
  		public FastWriter println(char c) {
  			return writeln(c);
  		}
  
  		public FastWriter println(int x) {
  			return writeln(x);
  		}
  
  		public FastWriter println(long x) {
  			return writeln(x);
  		}
  
  		public FastWriter println(double x, int precision) {
  			return writeln(x, precision);
  		}
  
  		public FastWriter print(int... xs) {
  			return write(xs);
  		}
  
  		public FastWriter print(long... xs) {
  			return write(xs);
  		}
  
  		public FastWriter println(int... xs) {
  			return writeln(xs);
  		}
  
  		public FastWriter println(long... xs) {
  			return writeln(xs);
  		}
  
  		public FastWriter println(char[] line) {
  			return writeln(line);
  		}
  
  		public FastWriter println(char[]... map) {
  			return writeln(map);
  		}
  
  		public FastWriter println(String s) {
  			return writeln(s);
  		}
  
  		public FastWriter println() {
  			return writeln();
  		}
  	}
  
  	// Fast Inputs
  	static class FastScanner {
  		//I don't understand how this works lmao
  		private int BS = 1 << 16;
  		private char NC = (char) 0;
  		private byte[] buf = new byte[BS];
  		private int bId = 0, size = 0;
  		private char c = NC;
  		private double cnt = 1;
  		private BufferedInputStream in;
  
  		public FastScanner() {
  			in = new BufferedInputStream(System.in, BS);
  		}
  
  		public FastScanner(String s) {
  			try {
  				in = new BufferedInputStream(new FileInputStream(new File(s)), BS);
  			} catch (Exception e) {
  				in = new BufferedInputStream(System.in, BS);
  			}
  		}
  
  		private char getChar() {
  			while (bId == size) {
  				try {
  					size = in.read(buf);
  				} catch (Exception e) {
  					return NC;
  				}
  				if (size == -1)
  					return NC;
  				bId = 0;
  			}
  			return (char) buf[bId++];
  		}
  
  		public int nextInt() {
  			return (int) nextLong();
  		}
  
  		public int[] readArray(int N) {
  			int[] res = new int[N];
  			for (int i = 0; i < N; i++) {
  				res[i] = (int) nextLong();
  			}
  			return res;
  		}
  
  		public long[] readArrayLong(int N) {
  			long[] res = new long[N];
  			for (int i = 0; i < N; i++) {
  				res[i] = nextLong();
  			}
  			return res;
  		}
  
  		public int[][] readArrayMatrix(int N, int M, int Index) {
  			if (Index == 0) {
  				int[][] res = new int[N][M];
  				for (int i = 0; i < N; i++) {
  					for (int j = 0; j < M; j++)
  						res[i][j] = (int) nextLong();
  				}
  				return res;
  			}
  			int[][] res = new int[N][M];
  			for (int i = 1; i <= N; i++) {
  				for (int j = 1; j <= M; j++)
  					res[i][j] = (int) nextLong();
  			}
  			return res;
  
  		}
  
  		public long[][] readArrayMatrixLong(int N, int M, int Index) {
  			if (Index == 0) {
  				long[][] res = new long[N][M];
  				for (int i = 0; i < N; i++) {
  					for (int j = 0; j < M; j++)
  						res[i][j] = nextLong();
  				}
  				return res;
  			}
  			long[][] res = new long[N][M];
  			for (int i = 1; i <= N; i++) {
  				for (int j = 1; j <= M; j++)
  					res[i][j] = nextLong();
  			}
  			return res;
  
  		}
  
  		public long nextLong() {
  			cnt = 1;
  			boolean neg = false;
  			if (c == NC)
  				c = getChar();
  			for (; (c < '0' || c > '9'); c = getChar()) {
  				if (c == '-')
  					neg = true;
  			}
  			long res = 0;
  			for (; c >= '0' && c <= '9'; c = getChar()) {
  				res = (res << 3) + (res << 1) + c - '0';
  				cnt *= 10;
  			}
  			return neg ? -res : res;
  		}
  
  		public double nextDouble() {
  			double cur = nextLong();
  			return c != '.' ? cur : cur + nextLong() / cnt;
  		}
  
  		public double[] readArrayDouble(int N) {
  			double[] res = new double[N];
  			for (int i = 0; i < N; i++) {
  				res[i] = nextDouble();
  			}
  			return res;
  		}
  
  		public String next() {
  			StringBuilder res = new StringBuilder();
  			while (c <= 32)
  				c = getChar();
  			while (c > 32) {
  				res.append(c);
  				c = getChar();
  			}
  			return res.toString();
  		}
  
  		public String nextLine() {
  			StringBuilder res = new StringBuilder();
  			while (c <= 32)
  				c = getChar();
  			while (c != '\n') {
  				res.append(c);
  				c = getChar();
  			}
  			return res.toString();
  		}
  
  		public boolean hasNext() {
  			if (c > 32)
  				return true;
  			while (true) {
  				c = getChar();
  				if (c == NC)
  					return false;
  				else if (c > 32)
  					return true;
  			}
  		}
  	}
  
  }
  