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

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