#include<iostream>
using namespace std;

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

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

ll merge(int A[],int n,int left,int mid,int right){
  int i,j,k;
  ll cnt = 0;
  int n1 = mid-left;
  int n2 = right-mid;
  for(int t=0;t<n1;t++) L[t] = A[left+t];
  for(int t=0;t<n2;t++) R[t] = A[mid+t];
  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;
}

ll mergeSort(int A[],int n,int left,int right){
  int mid;
  ll 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;

  cin >> n;
  for(int i=0;i<n;i++){
    cin >> A[i];
  }

  ll ans = mergeSort(A,n,0,n);
  cout << ans << endl;
  return 0;
}
