#include <iostream>
#include <string>
#include <algorithm>

using namespace std;

int main()
{
    string s;
    cin >> s;

    int ans=0;
    for(int i=0; i<s.length(); i++){
        if(s[i]>='0' && s[i]<='9') ans += s[i]-'0';
    }
    cout << ans << endl;

    return 0;
}