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