#include<iostream>
using namespace std;
#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;
 cin>>n;
 for(i=0;i<n;i++)cin>>A[i];
 llong ans = mergeSort(A,n,0,n);
 cout<<ans<<endl;
 return 0;
}
