#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
  #define _GLIBCXX_DEBUG
#else
  #define Debug(...) void(0)
#endif
using ll = long long;
#define rep(i, n) for (int i = 0; i < (n); ++i)

int main() {
  string s;
  cin >> s;
  int ans = 0;
  rep(i, s.size()) {
    string t = s.substr(0, i);
    string u = s.substr(i);
    if (t.empty() || u.empty()) continue;
    if (t.front() == '0' || u.front() == '0') continue;
    ans++;
  }
  cout << ans << endl;
  return 0;
}