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