//https://ncode.syosetu.com/n4830bu/289/
#include <bits/stdc++.h>
using namespace std;

int main() {
    string S;
    cin >> S;
    int maine = 0;
    for (auto&& c : S) {
        if (isdigit(c))
            maine += c - '0';
    }
    cout << maine << endl;
}