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

my %count;
while (<>) {
    my @F1 = split /\t/;
    my @F2 = split /\t/, <>;

    my ($num, $from, $to) = (@F1[ 1, 2 ], $F2[2] );
    ($from, $to) = ($to, $from) if $from > $to;
    ++$count{$num}{$from}{$to};
}