#define _USE_MATH_DEFIMES #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include const int MOD = 1'000'000'007; const int MOD2 = 998'244'353; const int INF = 1'000'000'000; //1e9 const int NIL = -1; const long long LINF = 1'000'000'000'000'000'000; // 1e18 const long double EPS = 1E-10L; template inline bool chmax(T &a, const S &b){ if(a < b){a = b; return true;} return false; } template inline bool chmin(T &a, const S &b){ if(b < a){a = b; return true;} return false; } template inline bool exist(Container &s, const T &e){ return (s.find(e) != std::end(s)); } template inline bool inside(T x, T lx, T rx){ return (std::clamp(x, lx, rx) == x); } template inline bool inside(T x, T y, T lx, T rx, T ly, T ry){ return inside(x, lx, rx) && inside(y, ly, ry); } int main(){ int cnt{}; std::string S; std::cin >> S; for(int i{1}, i_len{int(S.length())}; i < i_len; ++i){ if(S[i] != '0') ++cnt; } std::cout << cnt << std::endl; return 0; }