$N = trim(fgets(STDIN));
    $K = trim(fgets(STDIN));
    
    $Nx = array();
    for ($i = 0; $i < $N; $i++) 
    	$Nx[] = trim(fgets(STDIN));
    
    sort($Nx);
    echo ($Nx[$N-1] - $Nx[0]) . "\n";