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

int main() {
  string S; cin >> S;
  int ans = 0;
  for(int i = 0; i < (int)S.size(); i++){
    if('0' <= S[i] and S[i] <= '9'){
      ans += S[i]-48;
    }
  }
  cout << ans << endl;
}