description: You have a permutation: an array a = [a_1, a_2, …, a_n] of distinct integers from 1 to n. The length of the permutation n is odd.
  
  Consider the following algorithm of sorting the permutation in increasing order.
  
  A helper procedure of the algorithm, f(i), takes a single argument i (1 ≤ i ≤ n-1) and does the following. If a_i > a_{i+1}, the values of a_i and a_{i+1} are exchanged. Otherwise, the permutation doesn't change.
  
  The algorithm consists of iterations, numbered with consecutive integers starting with 1. On the i-th iteration, the algorithm does the following: 
  
    * if i is odd, call f(1), f(3), …, f(n - 2); 
    * if i is even, call f(2), f(4), …, f(n - 1). 
  
  
  
  It can be proven that after a finite number of iterations the permutation will be sorted in increasing order.
  
  After how many iterations will this happen for the first time?
  
  Input
  
  Each test contains multiple test cases. The first line contains the number of test cases t (1 ≤ t ≤ 100). Description of the test cases follows.
  
  The first line of each test case contains a single integer n (3 ≤ n ≤ 999; n is odd) — the length of the permutation.
  
  The second line contains n distinct integers a_1, a_2, …, a_n (1 ≤ a_i ≤ n) — the permutation itself. 
  
  It is guaranteed that the sum of n over all test cases does not exceed 999.
  
  Output
  
  For each test case print the number of iterations after which the permutation will become sorted in increasing order for the first time.
  
  If the given permutation is already sorted, print 0.
  
  Example
  
  Input
  
  
  3
  3
  3 2 1
  7
  4 5 7 1 3 2 6
  5
  1 2 3 4 5
  
  
  Output
  
  
  3
  5
  0
  
  Note
  
  In the first test case, the permutation will be changing as follows: 
  
    * after the 1-st iteration: [2, 3, 1]; 
    * after the 2-nd iteration: [2, 1, 3]; 
    * after the 3-rd iteration: [1, 2, 3]. 
  
  
  
  In the second test case, the permutation will be changing as follows: 
  
    * after the 1-st iteration: [4, 5, 1, 7, 2, 3, 6]; 
    * after the 2-nd iteration: [4, 1, 5, 2, 7, 3, 6]; 
    * after the 3-rd iteration: [1, 4, 2, 5, 3, 7, 6]; 
    * after the 4-th iteration: [1, 2, 4, 3, 5, 6, 7]; 
    * after the 5-th iteration: [1, 2, 3, 4, 5, 6, 7]. 
  
  
  
  In the third test case, the permutation is already sorted and the answer is 0.
solution: /* package codechef; // don't place package name! */
  import java.io.*;
  import java.lang.*;
  import java.util.*;
  import java.util.Collection;
  import static java.lang.Math.*;  
  public class Main implements Runnable 
  {  
       static int gcd(int a, int b)
      {
        if (b == 0)
          return a;
        return gcd(b, a % b);
      }
      static boolean isPerfect(int N)
      {
          if ((Math.sqrt(N) - Math.floor(Math.sqrt(N))) != 0)
              return false;
          return true;
      }
      static  int getClosestPerfectSquare(int N)
      {
          if (isPerfect(N)) 
          {
              return 0;
          }
          int aboveN = -1;
          int n1;
          n1 = N + 1;
          while (true) 
          {
              if (isPerfect(n1))
              {
                  aboveN = n1;
                  break;
              }
              else
                  n1++;
          }
          return aboveN;
      }
      static boolean sorted(int arr[],int n) 
      {
          for(int i=1;i<n;i++) 
          {
              if(arr[i]<arr[i-1]) 
              {
                  return false;
              }
          }
          return true;
      }
      public void run() 
      {
          InputReader s = new InputReader(System.in);
          PrintWriter out = new PrintWriter(System.out);
          int t = s.nextInt();
          while(t-- > 0)
          {
             int n=s.nextInt();
             int arr[]=new int[n];
              for(int i=0;i<n;i++) 
              {
                  arr[i]=s.nextInt();
              }
              int c=0;
              while(!sorted(arr,n)) 
              {
                  ++c;
                  if(c%2 == 0) {
                      for(int i=1;i<n-1;i+=2)
                       {
                          if(arr[i]>arr[i+1]) 
                          {
                              int temp=arr[i];
                              arr[i]=arr[i+1];
                              arr[i+1]=temp;
                          }
                      }
                  }
                  else {
                      for(int i=0;i<n-1;i+=2)
                       {
                          if(arr[i]>arr[i+1])
                           {
                              int temp=arr[i];
                              arr[i]=arr[i+1];
                              arr[i+1]=temp;
                          }
                      }
                  }
              }
              System.out.println(c);
          }
           out.close();
        }
      static class InputReader {
          private InputStream stream;
          private byte[] buf = new byte[1024];
          private int curChar;
          private int numChars;;
          private SpaceCharFilter filter;
          private BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
   
          public InputReader(InputStream stream) {
              this.stream = stream;
          }
          
          public int read() {
              if (numChars==-1) 
                  throw new InputMismatchException();
              
              if (curChar >= numChars) {
                  curChar = 0;
                  try {
                      numChars = stream.read(buf);
                  }
                  catch (IOException e) {
                      throw new InputMismatchException();
                  }
                  
                  if(numChars <= 0)               
                      return -1;
              }
              return buf[curChar++];
          }
       
          public String nextLine() {
              String str = "";
              try {
                  str = br.readLine();
              }
              catch (IOException e) {
                  e.printStackTrace();
              }
              return str;
          }
          public int nextInt() {
              int c = read();
              
              while(isSpaceChar(c)) 
                  c = read();
              
              int sgn = 1;
              
              if (c == '-') {
                  sgn = -1;
                  c = read();
              }
              
              int res = 0;
              do {
                  if(c<'0'||c>'9') 
                      throw new InputMismatchException();
                  res *= 10;
                  res += c - '0';
                  c = read();
              }
              while (!isSpaceChar(c)); 
              
              return res * sgn;
          }
          
          public long nextLong() {
              int c = read();
              while (isSpaceChar(c))
                  c = read();
              int sgn = 1;
              if (c == '-') {
                  sgn = -1;
                  c = read();
              }
              long res = 0;
              
              do {
                  if (c < '0' || c > '9')
                      throw new InputMismatchException();
                  res *= 10;
                  res += c - '0';
                  c = read();
              }
              while (!isSpaceChar(c));
                  return res * sgn;
          }
          
          public double nextDouble() {
              int c = read();
              while (isSpaceChar(c))
                  c = read();
              int sgn = 1;
              if (c == '-') {
                  sgn = -1;
                  c = read();
              }
              double res = 0;
              while (!isSpaceChar(c) && c != '.') {
                  if (c == 'e' || c == 'E')
                      return res * Math.pow(10, nextInt());
                  if (c < '0' || c > '9')
                      throw new InputMismatchException();
                  res *= 10;
                  res += c - '0';
                  c = read();
              }
              if (c == '.') {
                  c = read();
                  double m = 1;
                  while (!isSpaceChar(c)) {
                      if (c == 'e' || c == 'E')
                          return res * Math.pow(10, nextInt());
                      if (c < '0' || c > '9')
                          throw new InputMismatchException();
                      m /= 10;
                      res += (c - '0') * m;
                      c = read();
                  }
              }
              return res * sgn;
          }
          
          public String readString() {
              int c = read();
              while (isSpaceChar(c))
                  c = read();
              StringBuilder res = new StringBuilder();
              do {
                  res.appendCodePoint(c);
                  c = read();
              } 
              while (!isSpaceChar(c));
              
              return res.toString();
          }
       
          public boolean isSpaceChar(int c) {
              if (filter != null)
                  return filter.isSpaceChar(c);
              return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
          }
  
          
       
          public String next() {
              return readString();
          }
          
          public interface SpaceCharFilter {
              public boolean isSpaceChar(int ch);
          }
      }
      public static void main(String args[]) throws Exception {
          new Thread(null, new Main(),"Main",1<<26).start();
      }
  }
  
   
  
          
   
  