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

int main()
{
    string S;
    cin >> S;
    int N = S.size();
    int ans = 0;
    for (int i = 0; i < N; i++)
    {
        if ('1' <= S[i] && S[i] <= '9')
        {
            ans += S[i] - '0';
        }
    }
    cout << ans;
}