#!/usr/bin/perl
use warnings;
use strict;
use 5.010;

# The 3n + 1 problem (http://www.streamtech.nl/problemset/100.html)

my @pairs;
say "Input:";

while (defined ($_ = <STDIN>) && !/^\.$/) {
    if (!/^(\d+)\s+(\d+)$/ && $1 > 0 && $2 > 0) {
        chomp;
        say "Invalid input >$_<.";
        say 'Two non-zero positive integers are expected. Input ignored';
        next;
    }

    push @pairs, [$1, $2];
}

say "Output:";

for my $pair (@pairs) {
    my $maxLength = calcCycleLen ($pair->[0]);
    my $length2   = calcCycleLen ($pair->[1]);

    $maxLength = $length2 if $maxLength = $length2;
    say "@$pair $maxLength";
}


sub calcCycleLen {
    my ($number) = @_;
    my $length = 1;

    while ($number > 1) {
        $number = $number % 2 ? $number * 3 + 1 : $number / 2;
        ++$length;
    }

    return $length;
}