#include <iostream>
using namespace std;
const int N = 1e5 + 10;
typedef long long ll;
int q[N],temp[N];

ll merger_sort(int q[],int l,int r)
{
    if (l >= r)
        return 0;
    int m = l + (r - l) / 2;
    ll ans = merger_sort(q,l,m) + merger_sort(q,m + 1,r);
    int k = l,i = l,j = m + 1;
    while (i <= m && j <= r)
    {
        if (q[i] <= q[j])   temp[k++] = q[i++];
        else    ans += (m - i + 1),temp[k++] = q[j++];
    }
    while (i <= m)  temp[k++] = q[i++];
    while (j <= r)  temp[k++] = q[j++];
    for (k = l;k <= r;++k)  q[k] = temp[k];
    return ans;
}

int main(void)
{
    int n;
    scanf("%d",&n);
    for (int i = 0;i < n;++i)
        scanf("%d",&q[i]);
    printf("%lld",merger_sort(q,0,n - 1));
    return 0;
}