#include <cstdio>
#include <cstdlib>
#include <algorithm>
using namespace std;
int n;
int a[1055155];
int c[1000155];
long long ans;
void (int x,int y)
{
	if(x==y)
	return;
	int mid=(x+y)/2;
	merge(x,mid);
	merge(mid+1,y);
	int cnt=x;
	int i=x;
	int j=mid+1;
	while(i<=mid&&j<=y)
	{
		if(a[i]<=a[j])
		{
			c[cnt++]=a[i++];
		}
		else
		{
			c[cnt++]=a[j++];
			ans+=mid-i+1;
		}
	}
		while(i<=mid)
			c[cnt++]=a[i++];
		while(j<=y)
			c[cnt++]=a[j++];
		for(int i=x;i<=y;i++)
		a[i]=c[i];
}
int main()
{
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		scanf("%d",&a[i]);
	}
	merge(1,n);
	cout<<ans<<endl;
	return 0;
}