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

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