#include <stdio.h>

#define MAX 200000
#define SENTINEL 2000000000
typedef long long llong;

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

llong merge(int A[],int n,int left,int mid,int right){
  int i,j,k;
  llong cnt = 0;
  int n1 = mid -left;
  int 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] = SENTINEL;
  i = j = 0;
  for(k = left;k < right;k++){
    if(L[i] <= R[j]){
      A[k] = L[i++];
    } else{
      A[k] = R[j++];
      cnt += n1 - i;
    }
  }
  return cnt;
}

llong mergeSort(int A[] ,int n,int left,int right){
  int mid;
  llong v1,v2,v3;
  if(left + 1 < right){
    mid = (left + right)/2;
    v1 = mergeSort(A,n,left,mid);
    v2 = mergeSort(A,n,mid,right);
    v3 = merge(A,n,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,n,0,n);
  printf("%lld\n",ans);
  return 0;
}