#include<iostream>
#include<string>
using namespace std;

int main(){
  string s;
  cin >> s;

  int sum = 0;
  for(char x:s){
    if('0' <= x && x <='9'){
      sum += (int)x - '0'; 
    }
  }

  cout << sum << endl;
  
  return 0;
}