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

my $string1 = "IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIMMMMMMMMOOOOOOOOOOOOOOOOOOOOOOOOOOOMMMMMMMMMIIIIMMMMMMMMMMMMMOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOMMMMMMMMMIIIMMMMMMMMMMMOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOMMMMMMMMMMMMMIIIIIMMMMMMMMMMMOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOMMMMMMMMMIIIMMMMMMMMMOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOMMMMMMMMMMMIIIMMMMMMMMMOOOOOOOOOOOOOOOOOOOMMMMMMMMMIIIIIIIIIIIIIIIIIIIIIIIIIIIMMMMMMMMOMMMMMMMMMMMMM";
my $string2 = "IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIMMMMMMMMMMMMOOOOOOOOOOOOOOOOOMMMMMMMMMMMMMMMMIIIIIMMMMMMMMMMMMMOOOOOOOOOOOOOOOOOOOOOOOOMMMMMMMMMMMMMMMIIIMMMMMMMMMMMMMMOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOMMMMMMMMMMMMMMMIIIMMMMMMMMMMMMMMMOOOOOOOOOOOOOOOOOOOOOOOOOOOOMMMMMMMMMMMMMMIIIMMMMMMMMMMMMMMMOOOOOOOOOOOOOOOOOOOOOOOOOMMMMMMMMMMMMMMIIIMMMMMMMMMMMMOOOOOOOOOOOOOOOMMMMMMMMMMIIIIIIMMMMMMMMMMMMOOOOOOOOOOOOOOOOOMMMMMMMMMMMMII";

my $correct_topo = 1;

# Test if they start with the same letter
if (substr($string1,0,1) ne substr($string2,0,1)) {
   undef $correct_topo;  
}

# Test if M counts match up
my $count1;
$count1++ while $string1 =~ /M+/g;
my $count2;
$count2++ while $string2 =~ /M+/g;
if ($count1 != $count2) {
    undef $correct_topo;
}

# Test if M's line up
my $start = index($string1, 'M');
$start = index($string2, 'M', $start); # In case it starts later
while ($start != -1) { # While I haven't missed anything
    $count1--; # See of the counts line up, in case we skip collisions
    if (    substr($string1,$start,5) ne 'MMMMM'
        or  substr($string2,$start,5) ne 'MMMMM')
    {
        undef $correct_topo;
        last;
    }
    substr($string1,$start) =~ /[^M]/ or last; # Ran out of string
    $start = index $string1, 'M', $-[0]+$start; # Start of next set of M's
    $start = index $string2, 'M', $start if $start != -1; # But this chunk might start later
}

undef $correct_topo if $count1 != 0;