#include<bits/stdc++.h>

using namespace std;

long long a[114514], r[114514];
long long ans = 0;
void mosort (long long s, long long t)
{
if(s == t) return ;
long long mid = (s + t) / 2;
mosort(s, mid);
mosort(mid + 1, t);
int i = s, j = mid + 1, k = s;
while(i <= mid && j <= t)
{
if(a[i] <= a[j])
{
r[k] = a[i];
k++;
i++;
}
else
{
r[k] = a[j];
k++;
j++;
ans+=mid-i+1;
}
}
while(i <= mid)
{
r[k] = a[i];
k++;
i++;
}
while(j <= t)
{
r[k] = a[j];
k++;
j++;
}
for(int i = s; i <= t; i++) a[i] = r[i];
}

int main()
{
int n;
cin >> n;
for(int i = 1; i <= n; i++)
{
cin >> a[i];
}
mosort(1,n);
cout << ans;
return 0;
}