#include<stdio.h>
#define MAX 200000
#define INFTY  2000000000

typedef long long llong;

int L[MAX/2+2], R[MAX/2+2];

llong merge(int A[], int left, int mid, int right){
  int i, j, k, n1, n2;
  llong cnt = 0;

  n1 = mid - left;
  n2 = right - mid;
  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] = INFTY;
  i = j = 0;
  for( k = left ; k < right ; k++ ){
    if( L[i] <= R[j] ){
      A[k] = L[i];
      i = i +1;
    }
    else {
      A[k] = R[j];
      j = j + 1;
      cnt += n1 - i;
    }
  }
  return cnt;
}

llong mergeSort(int A[], int left, int right){
  int mid;
  llong v1, v2, v3;
  
  if( left + 1 < right ){
    mid = ( left + right ) / 2;
    v1 = mergeSort(A, left, mid);
    v2 = mergeSort(A, mid, right);
    v3 = merge(A, left, mid, right);
    return v1+v2+v3;
  }
  else return 0;
}

int main(){
  int A[MAX], n, i;

  scanf("%d", &n);
  for( i = 0 ; i < n ; i++ ){
    scanf("%d", &A[i]);
  }

  llong ans = mergeSort(A, 0, n);
  printf("%d\n", ans);

  return 0;
}

