#include <iostream>
using namespace std;
int main(){
    int ans=0;
    string str;
    cin >> str;
    for(int i=0;i<str.size();i++){
        if(0 <= str[i]-'0' && str[i]-'0'<=9)ans+=str[i]-'0';
    }
    cout << ans << endl;
    return 0;
}