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

int main()
{
    string A;
    int sum = 0;
    cin >> A;
    for (int i = 0; i < A.size(); ++i){
        char c = A[i];
        if (48 <= c && c <= 57){
            sum += (c-48);
        }
    }

    cout << sum << endl;
    return 0;
}