#23456789_123456789_123456789_123456789_123456789_123456789_
$_=pop;$l=$_,($_+=$ARGV[0]/$_)/=2while$l-$_;print

##</code><code>##

# 44
#23456789_123456789_123456789_123456789_123456789_
$a=pop;($a+=$ARGV[0]/$a)/=2for-9..99;print$a