#include <iostream>
#include <string>
using namespace std;
using ll = long long;

int main() {
    string s;
    cin >> s;
    int res = 0;
    for(int i=0; i<s.size(); ++i) {
        if(isdigit(s[i])) {
            res += s[i]-'0';
        }
    }
    cout << res << endl;
}