// 2023 IUSB Programming Competition
// Round 1 Problem 1
// String Mining
// Solution by Liguo Yu

#include <iostream>
#include <string>

using namespace std;

int main()
{
    string s;
    cin >> s;
    
    int sum = 0;
    for(int i=0; i<s.length(); i++)
    {
        if(isdigit(s[i]))
        {
            sum = sum + (s[i] - '0');
        }
    }
    
    cout << sum << endl;
    
    return 0;
}