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

int main() {
  string s;
  int ans = 0;
  for ( int i = 0; i < s.length(); i++ ) {
    ans += ( isdigit(s[i]) ) ? s[i]-'0' : 0;
  }
  cout << ans << endl;
  return 0;
}