a, b = 0, 1
while b < 50:
	print(a, b)
	a, b = b, a + b

##</code><code>##

old_a = a
a = b
b = old_a + b

##</code><code>##

 
use warnings;
use 5.18.2;

my ($a, $b) = (0, 1);
while ($b < 50) {
	say "$a $b";
	my $old_a = $a;
	$a = $b;
	$b = $old_a + $b;
}