#include <bits/stdc++.h>
using namespace std;
#define REP(i,n) for (int i = 0; i < n; ++i)
typedef long long ll;
// Welcome to my source code!

int main() {
    string s;
    cin >> s;
    int ans = 0;
    for (char x : s) {
        if (isdigit(x)) ans += x - '0';
    }
    cout << ans << endl;
}