#include <stdio.h>
#include <string.h>
#include <math.h>
int main(void) {
  int N;
  int i;
  int a[1000000];
  int t;
  int cnt = 0; 
  scanf("%d", &N);
  for (i = 0; i < N; i++) {
    scanf("%d", &a[i]);
  }
  for (i = N-1; i > 0; i--) {
    if (a[i-1] > a[i]) {
      t = a[i-1];
      a[i-1] = a[i];
      a[i] = t;
      cnt++;
    }
  }
  printf("%d",cnt);
  return 0;
}