#include <iostream>
#include <string>

/* this was clipped out of out main experiment to help find out how many
   unique words there are in the text file. It was run like this:

   a.out < /home/www/text/abbot/flatland | sort -u | wc

   which revealed that there are 4767 unique words in the file
*/

string cleanup(string s)
{ string r = "";
  for (int i = 0; i < s.length(); i += 1)
  { char c = s[i];
    if (isalpha(c))
      r += (char)tolower(c); }
  return r; }

void main()
{ while (true)
  { string s;
    cin >> s;
    if (cin.fail())
      break;

    s = cleanup(s);
    if (s == "")
      continue;

    cout << s << "\n"; } }