#include <stdio.h>
#include <limits.h>
 
#define MAX 200000
#define INF INT_MAX
 
void merge(int*, int, int, int);
void mergesort(int*, int, int);
 
int ans;
 
int n, a[MAX];
 
int main(){
  int i;
 
  scanf("%d" ,&n);
  for(i = 0 ; i < n ; i++){
    scanf("%d" ,a + i);
  }
  mergesort(a,0,n);
  printf("%d\n" ,ans);
 
  return 0;
}
 
void merge(int a[], int left, int mid, int right){
  int n1 = mid - left, n2 = right - mid;
  int L[n1+1], R[n2+1], i, j, k;
  
  for(i = 0 ; i < n1 ; i++){
    L[i] = a[left + i];
  }
  
  for(i = 0 ; i < n2 ; i++){
    R[i] = a[mid + i];
  }
  
  L[n1] = R[n2] = INF;
  
  for(i = 0, j = 0, k = left ; k < right ; k++){
    if(i < n1 && (j == n2 || L[i] <= R[j])){
      a[k] = L[i++];
    }else{
      ans += (n1 + n2) / 2 - i;
      a[k] = R[j++];
    }
  }
}
  
void mergesort(int a[], int left, int right){
  int mid;
  
  if(left + 1 < right){
    mid = (left + right) / 2;
    mergesort(a, left, mid);
    mergesort(a, mid, right);
    merge(a, left, mid, right);
  }
}
