#include <bits/stdc++.h>   using namespace std;   char a;   int n, sum, flag = 1;   int main() {     cin >> n;     for (int i = 0; i < n; i++) {       cin >> a;       if (a !=  0 )         sum++, flag = 1;       else if (flag == 1 && a ==  0 ) {         cout << sum;         sum = 0;         flag = 0;       } else if (a ==  0  && flag == 0)         cout <<  0 ;     }     cout << sum;   }   