#include"bits/stdc++.h" //#include<boost/multi_array.hpp> //#include<boost/optional.hpp> //#include<boost/range/irange.hpp> //#include<boost/range/algorithm.hpp> //#include<boost/range/adaptors.hpp> using namespace std; //namespace adaptor = boost::adaptors; #define rep(i,n) for (int i = 0; i < (n); ++i) using namespace std; using ll = long long; using P = pair<int, int>; #include<bits/stdc++.h> using namespace std; //int mod = 1000000007; void Main() { string c; cin >> c; int zerocou = 0; rep(i, c.size()){ if(c[i] == '0'){ zerocou++; } } cout << c.size() -1 -zerocou << endl; } int main() { std::cin.tie(nullptr); std::ios_base::sync_with_stdio(false); std::cout << std::fixed << std::setprecision(15); Main(); return 0; }