#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;
  llong ans;

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

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

  return 0;
}