#!usr/bin/perl
use strict;
use warnings;
use diagnostics;
my $range = 100;
my $random_number = int(rand($range));
my $answer = 0;

print "Do you accept this challenge? ";

Do  {
	chomp (my $response = <>);	
	if ($response eq 'yes' || 'Yes' || 'YES' || 'y') {
		$answer = $answer + 1;
} 

	elsif ($response eq 'no' || 'No' || 'NO' || 'n') {
		$answer = $answer + 2;
	
	} else {
		print "Please respond with 'yes' or 'no'\n\n";
	}	
}until $answer > 0;