#include <iostream>

int maxDepth, steps, bestSteps, p;

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

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

  doit(s, curDep, i), doit(s, curDep, i);
}

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