#include <iostream>
using namespace std;

string s;

int main(){
    cin >> s;

    int sum = 0;

    for(int i = 0; i < s.size(); i++){
        if(s[i] >= '0' && s[i] <= '9'){
            sum += (s[i] - '0');
        }
    }

    cout << sum << endl;
}