#include <bits/stdc++.h>
using namespace std;
int N;
char s[110];
int solve(int n) {
  if (n == N) return 0;
  if (s[n] == '0') return 1;
  return 1 + solve(n + 1);
}
int main() {
  scanf("%d %s", &N, s);
  printf("%d\n", solve(0));
  return 0;
}
