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

int main(){
  string s;
  int sum = 0;
  
  cin >> s;
  
  for(int i=0;i<s.size();i++){
    if(s.at(i)>='0'&&s.at(i)<='9')
    	sum += s.at(i)-'0';
  }
  
  cout << sum << endl;
  
  return 0;
}