#include <bits/stdc++.h>
using namespace std;
#define repeat(i,n) for (int i = 0; (i) < (n); ++ (i))

int main() {
    string s; cin >> s;
    int sum = 0;
    for (char c : s) {
        if (c >= '0' && c <= '9') sum += c - '0';
    }
    cout << sum << endl;
}