#include<iostream>
#include<algorithm>
#include<stdio.h>
#include<stdlib.h>
#include<vector>
#include<string>
#include<sstream>
using namespace std;


int main(){

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


  return 0;
}