#include<iostream>
#include<algorithm>
#include<string>
using namespace std;
//typedef __int64 LL;
int main(){
    string s;
    int sum=0;
    cin>>s;
    for(int i=0;i<s.size();i++){
        if(48<=s[i] && s[i]<=57)sum+=s[i]-48;
    }
    cout<<sum<<endl;
    return 0;
}