#include <iostream>
#include <string>
using namespace std;

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