#include <bits/stdc++.h>
using namespace std;

int main() {
    string s;
    cin >> s;
    int ans = 0;
    for(int i=0;i<s.size();i++) {
        int a = s[i] - '0';
        if(a < 0 || a > 9) continue;
        ans += a;
    }
    cout << ans << endl;
}