#include <iostream>
#include <string>
#include <cstdio>
#include <cstdlib>
using namespace std;

int main() {
    int sum = 0;
    string s; cin >> s;

    for (char ch : s) {
        if(ch >= '0' && ch <= '9'){
            sum += ch - '0';
        }
    }
    
    cout << sum << endl;
	return 0;
}