#include <iostream>
using namespace std;

int main(void)
{
    string s; cin >> s;
    int t=0;
    
    for(int i=0;i<s.length();i++)
    {
        if('1' <= s[i] && s[i] <= '9') t += s[i] - '0';
    }
    cout << t << endl;
}