#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
using namespace std;

int main(){
    string s;
    cin>>s;
    int ans=0;
    for(auto c:s){
        if(c>='0'&&c<='9') ans+=c-'0';
    }
    cout<<ans<<endl;
    return 0;
}