#include<bits/stdc++.h>
using namespace std;
int s[500005] = {};
int tmp[500005] = {};
long long int ans = 0;
void merge_sort(int l, int r){
    if(r-l==0){
        return;
    }else if(r-l==1){
        if(s[r]<s[l]){
            swap(s[r],s[l]);
            ans++;
        }
        return;
    }
    int m = (l+r)/2;
    merge_sort(l, m);
    merge_sort(m+1, r);
    int L = l, R = m + 1, k = 0, cnt = 0;
    while(L<=m&&R<=r){
        if(s[L]<=s[R]){
            tmp[k] = s[L];
            k++;
            L++;
            ans += cnt;
        }else{
            tmp[k] = s[R];
            k++;
            R++;
            cnt++;
        }
    }
    while(L<=m){
        ans += cnt;
        tmp[k] = s[L];
        k++;
        L++;
    }
    while(R<=r){
        tmp[k] = s[R];
        R++;
        k++;
    }
    for(int i = 0 ; i < k ; i++){
        s[l+i] = tmp[i];
    }
    return;
}
int main(){
    int n;
    ans = 0;
    cin >> n;
    for(int i = 0 ; i < n ; i++){
        cin >> s[i];
    }
    merge_sort(0,n-1);
    cout << ans;
    return 0;
}