<?php
$N = trim(fgets(STDIN));
$K = trim(fgets(STDIN));
$max = 1;
$min = 1000;
for ($i = 0; $i < $N; $i++) {
	$n = trim(fgets(STDIN));
	$max = max($max, $n);
	$min = min($min, $n);
}
print $max - $min;
?>