#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define endl "\n"

int main() {
    string s;
    cin >> s;

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

    cout << ans << endl;
    return 0;
}