#!/usr/bin/perl

use strict;
use warnings;

no warnings 'recursion';

my %orbs;
while (<>) {
    chomp;
    my ($parent, $child) = split( /\)/ );
    push( @{$orbs{$parent}}, $child );
}

# Recursive function to find YOU and SAN and their closest common parent.
sub walk_tree {
    my ($node, $depth) = @_;

    if (!exists $orbs{$node}) {
        return ($node => $depth);
    }

    my %ret;
    foreach my $child (@{$orbs{$node}}) {
        %ret = (%ret, &walk_tree( $child, $depth + 1 ));
    }

    if (exists $ret{YOU} && exists $ret{SAN}) {
        print "Transfers: ", $ret{YOU} + $ret{SAN} - 2 * $depth - 2, "\n";
        exit (0);
    }

    return (%ret);
}

&walk_tree( 'COM', 0 );