#include <stdio.h>
#define MAX 200000
#define INFTY 1000000001

int L[MAX/2+1], R[MAX/2+1], count = 0;

void merge(int *A, int left, int mid, int right) {
  int i, j, k;
  int n1 = mid - left;
  int n2 = right - mid;
  //L[0...n1], R[0...n2] を生成
  for (i = 0; i < n1; i++)
    L[i] = A[left + i];
  for (i = 0; i < n2; i++)
    R[i] = A[mid + i];
  L[n1] = INFTY;
  R[n2] = INFTY;
  i = 0;
  j = 0;
  for (k = left; k < right; k++) {
    if (L[i] <=  R[j]) {
      i++;
    } else {
      j++;
      count++;
    }
  }
}

void mergeSort(int *A, int left, int right) {
  if (left+1 < right) {
    int mid = (left + right)/2;
    mergeSort(A, left, mid);
    mergeSort(A, mid, right);
    merge(A, left, mid, right);
  }
}

int main() {
  int n, i, a[MAX];
  scanf("%d", &n);
  for(i = 0; i < n; i++) {
    scanf("%d", &a[i]);
  }
  mergeSort(a, 0, n);
  if(n % 2 == 1) count--;
  printf("%d\n", count);
  return 0;
}

