#include<bits/stdc++.h>
using namespace std;
const int N=5e6+2840;
long long n,ans,a[N],b[N];
void m(int l,int r){
	if(l==r)return;
	int mid=l+r>>1;
	m(l,mid);
	m(mid+1,r);
	int i=l,j=mid+1,k=l;
	while(i<=mid&&j<=r){
		if(a[i]<=a[j]){
			b[k++]=a[i++];
		}else{
			b[k++]=a[j++];
			ans+=mid-i+1; 
		}
	} 
	while(i<=mid){
		b[k++]=a[i++];
	}
	while(j<=r)
		b[k++]=a[j++];
		for(int i=l;i<=r;i++)
		a[i]=b[i];
}
int main(){
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>a[i];
	}
	m(1,n);
	cout<<ans;
	return 0;
}
//带飞