/* This program is free software; you can redistribute it and/or modify it under  
 * the terms of the GNU General Public License as published by the Free Software  
 * Foundation; either version 2 of the License, or (at your option) any later     
 * version.                                                                       
 *                                                                                  
 * This program is distributed in the hope that it will be useful, but WITHOUT    
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS  
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. 
 * 
 * Find a number in a given range that has the longest Collatz sequence.
 * http://en.wikipedia.org/wiki/Collatz_conjecture
 *
 */

{
   int low, high;

   int winner, winnerlen;
   int cur, curlen;

   int i;

   low = 2;         // invariant: low > 1
   high = 4096;

   winner = low; winnerlen = 1;

   for (i = low; i <= high; i ++){
      cur = i; curlen = 1;
      while (cur != 1){
        if (cur % 2 == 0) cur /= 2;
        else cur = 3 * cur + 1;
        ++ curlen;
      }

      if (curlen > winnerlen) winner = i, winnerlen = curlen;
   }

   writeint winner;

   while (winner != 1) {
      if (winner % 2 == 0) winner /= 2;
      else winner = 3 * winner + 1;
      writeint winner;
   }
   writeint winnerlen;
}