#include <iostream>
using namespace std;

int maxDepth, steps, bestSteps;

int doit(const string& s, int curDep, int i)
{
  if (s[i] == '0') return 1;

  ++steps;
  if (++curDep > maxDepth)
    maxDepth = curDep, bestSteps = steps;

  int l = 1 + doit(s, curDep, i + 1);
  return l + doit(s, curDep, i + l);
}

int main()
{
  string s;
  for (int c = 0; c < 10; ++c) {
    cin >> s; cin >> s;
    maxDepth = -1, steps = 0, bestSteps = -1;
    doit(s, 0, 0);
    cout << bestSteps << endl;
  }
}