#include<bits/stdc++.h>
using namespace std;

int main(){
    string s;
    cin >> s;
    int l = s.size();
    
    long long sum=0;
    for(int i=0; i<l; i++){
        if('a' <=s[i] && s[i] <= 'z') continue;
        sum += (s[i]-'0');
    }
    cout << sum << endl;
}