#include<bits/stdc++.h>
using namespace std;
long long n,s,b[1250005],c[2500000],i;
void px(long l,long r)
{
	if(l==r)return;
	long mid=(l+r)/2;
	long k=l,i=l,j=mid+1;
	px(l,mid);
	px(mid+1,r);
	while(i<=mid&&j<=r)
		if(b[i]<=b[j])c[k++]=b[j++];
		else c[k++]=b[i++],s=(s+r-j+1);
	while(i<=mid)c[k++]=b[i++];
	while(j<=r)c[k++]=b[j++];
	for(i=l;i<=r;i++)b[i]=c[i];
}
int main()                                                                                                                                                        
{
   cin>>n;
   for(i=1;i<=n;i++)cin>>b[i]; 
	px(1,n);
   cout<<s<<endl;
   return 0;
}