print "Think of a number between 1 and 10\n";
$user_answer = <STDIN>;
$program_guess = 0;

while ($user_answer ne 'YES') 
{
   $program_guess++;
   print "Is the number you thought of $program_guess ? Answer yes, higher or lower\n"; 
   $answer = <STDIN>;
   chomp $user_answer;
}
print "Program finished. The number you guessed was $program_guess.\n";