#include <bits/stdc++.h>
#define MAX 100005
#define ll long long
using namespace std;

struct so {
    int vt, nw, old;
};

so b[MAX];
int a[MAX],n;
ll f[MAX];
ll kq;

bool cmp(so x, so y)
{
    return x.old<y.old;
}

ll getBit(int x)
{
    ll kq=0;
    for (; x>0; x= x& (x-1)) kq+=f[x];
    return kq;
}
void update(int x)
{
    for (; x<= MAX; x+= x& (-1)*x)
    {
        f[x]++;
    }
}

int main()
{

    cin >> n;
    for (int i=0; i<n; i++)
    {
        cin >> b[i].old;
        b[i].vt=i;
        a[i]=b[i].old;
    }

    sort(b,b+n, cmp);

    int dem=1;
    b[0].nw=1;
    for (int i=1; i<n; i++)
    {
        if (b[i].old!=b[i-1].old)
        {
             dem++;
        }
        b[i].nw=dem;

    }
    for (int i=0; i<n; i++)
    {
        a[b[i].vt]=b[i].nw;
    }
    for (int i=n-1; i>=0; i--)
    {
        kq+=getBit(a[i]);
        update(a[i]+1);
    }
    cout<<kq;
}