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 java.io.BufferedWriter;
  import java.io.DataInputStream;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.OutputStreamWriter;
  
  
  
  public class Main {
  	static class Reader 
      { 
          final private int BUFFER_SIZE = 1 << 16; 
          private DataInputStream din; 
          private byte[] buffer; 
          private int bufferPointer, bytesRead;
  public Reader() 
          { 
              din = new DataInputStream(System.in); 
              buffer = new byte[BUFFER_SIZE]; 
              bufferPointer = bytesRead = 0; 
          }
  public Reader(String file_name) throws IOException 
          { 
              din = new DataInputStream(new FileInputStream(file_name)); 
              buffer = new byte[BUFFER_SIZE]; 
              bufferPointer = bytesRead = 0; 
          }
  public String readLine() throws IOException 
          { 
              byte[] buf = new byte[64]; // line length 
              int cnt = 0, c; 
              while ((c = read()) != -1) 
              { 
                  if (c == '\n') 
                      break; 
                  buf[cnt++] = (byte) c; 
              } 
              return new String(buf, 0, cnt); 
          }
  public int nextInt() throws IOException 
          { 
              int ret = 0; 
              byte c = read(); 
              while (c <= ' ') 
                  c = read(); 
              boolean neg = (c == '-'); 
              if (neg) 
                  c = read(); 
              do
              { 
                  ret = ret * 10 + c - '0'; 
              }  while ((c = read()) >= '0' && c <= '9');
  if (neg) 
                  return -ret; 
              return ret; 
          }
  public long nextLong() throws IOException 
          { 
              long ret = 0; 
              byte c = read(); 
              while (c <= ' ') 
                  c = read(); 
              boolean neg = (c == '-'); 
              if (neg) 
                  c = read(); 
              do { 
                  ret = ret * 10 + c - '0'; 
              } 
              while ((c = read()) >= '0' && c <= '9'); 
              if (neg) 
                  return -ret; 
              return ret; 
          }
  public double nextDouble() throws IOException 
          { 
              double ret = 0, div = 1; 
              byte c = read(); 
              while (c <= ' ') 
                  c = read(); 
              boolean neg = (c == '-'); 
              if (neg) 
                  c = read();
  do { 
                  ret = ret * 10 + c - '0'; 
              } 
              while ((c = read()) >= '0' && c <= '9');
  if (c == '.') 
              { 
                  while ((c = read()) >= '0' && c <= '9') 
                  { 
                      ret += (c - '0') / (div *= 10); 
                  } 
              }
  if (neg) 
                  return -ret; 
              return ret; 
          }
  private void fillBuffer() throws IOException 
          { 
              bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE); 
              if (bytesRead == -1) 
                  buffer[0] = -1; 
          }
  private byte read() throws IOException 
          { 
              if (bufferPointer == bytesRead) 
                  fillBuffer(); 
              return buffer[bufferPointer++]; 
          }
  public void close() throws IOException 
          { 
              if (din == null) 
                  return; 
              din.close(); 
          } 
      } 
      static Reader sc=new Reader();
      static BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(System.out));
      public static void main(String args[])throws IOException
      {
          
          Reader sc=new Reader();
          int t=inputInt();
         
        
          for (int i = 0; i<t; i++) {
          	int a = inputInt();
          	int b = inputInt();
          	int c = inputInt();
          	
          	int subst = Math.abs(a-b) - 1;
          	int upper = Math.max(a,b) + subst - (Math.min(a,b)-1);
          	if (subst < (Math.min(a,b)-1) ) {
          		System.out.println(-1);
          		continue;
          	}else if (upper < c) {
          		System.out.println(-1);
          		continue;
          	}else {
  //        		System.out.println(upper + "------");
          		int ans = c <= upper/2 ? c+(upper/2) : c-(upper/2);
          		System.out.println(ans);
          	}
          	
          }
         
          
          
          bw.flush();
          bw.close();
      }
      public static int inputInt()throws IOException
      {
          return sc.nextInt();
      }
      public static long inputLong()throws IOException
      {
          return sc.nextLong();
      }
      public static double inputDouble()throws IOException
      {
          return sc.nextDouble();
      }
      public static String inputString()throws IOException
      {
          return sc.readLine();
      }
      public static void print(String a)throws IOException
      {
          bw.write(a);
      }
      public static void printSp(String a)throws IOException
      {
          bw.write(a+" ");
      }
      public static void println(String a)throws IOException
      {
          bw.write(a+"\n");
      }
  }
  