#!/usr/local/bin/perl 

print ("What is 17 plus 26?\n"); 
$correct_answer = 43; # the correct answer 
$input_answer = <STDIN>; 
chop ($input_answer); 
until ($input_answer == $correct_answer) { 
    print ("Wrong! Keep trying!\n"); 
    $input_answer = <STDIN>; 
    chop ($input_answer); 
} 
print ("You've got it!\n");