#include <bits/stdc++.h>
#define ll long long
using namespace std;
int li[1000001];
int li2[1000001];
ll ans = 0;
void merge_sort(int L, int R) {
if (L == R)
return;
int mid = (L + R) >> 1;
merge_sort(L, mid);
merge_sort(mid + 1, R);
int l = L, ln = mid;
int r = mid + 1, rn = R;
int st = L;
ll cnt = 0;
while (l <= ln && r <= rn) {
if (li[l] <= li[r]){
ans += cnt;
li2[st++] = li[l++];
}
else{
cnt++;
li2[st++] = li[r++];
}
}
while (l <= ln){
ans += cnt;
li2[st++] = li[l++];
}
while (r <= rn)
li2[st++] = li[r++];
for (int i = L; i <= R; i++)
li[i] = li2[i];
};
int main() {
int n;
scanf("%d", &n);
for (int i = 1; i <= n; i++)
scanf("%d", &li[i]);
merge_sort(1, n);
printf("%lld", ans);
}