#!/usr/bin/perl
$good=0;
for($i=1;$i<=1000000;$i++)
{
	$n=0;
	if(rand(100)<=10){$n++};
	if(rand(100)<=10){$n++};
	if(rand(100)<=10){$n++};
	if(rand(100)<=10){$n++};
	if ($n>=3) {$good++};
}
print $good/1000000;