// 4 задача
#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
using namespace std;
int main()
{
    int k;
    cin >> k;
    vector <string> strings;
    vector <int> num(k);
    vector <int> count(k);
    string d, n;
    int m;
    for (int i = 0; i < k; i++) {
        cin >> d;
        strings.push_back(d);
    }
    for (int i = 0; i < k; ++i) {
        n = strings[i];
        m = n.size();
        for(int j = 0; j < m; ++j)
            if (n[j] == '1') {
                num[i] = j;
                break;
            }
        }
    string a;
    int b;
    for (int i = 0; i < k; ++i) {
        a = strings[i];
        b = a.size();
        for (int j = num[i]; j < b; j++) {
            if (a[j] == '0') {
                count[i]++;
            }
        }
    }
    return 0;
}