Codeforce A. Milking cows

#include<iostream>
#include<cstring>
#include<cstdio>
using namespace std; 
#define N 200005 
long long int ans, cow[N], lose[N];  
int main(int argc, char const *argv[]) 
{
    int n; 
    /* freopen("in.c", "r", stdin); */ 
    while(cin >> n)
    {
        ans = 0; 
        memset(lose, 0, sizeof(lose)); 
        for(int i = 1;i <= n;i ++)
        {
            cin >> cow[i]; 
            lose[i] = lose[i-1] + cow[i]; 
            if(cow[i] == 0)
                ans += lose[i];  
        }
        cout << ans << endl; 
    }
    return 0; 
}