#!/usr/bin/env perl
# Remove biallelic SNPs

while (<STDIN>) {
    if ($_ =~ /^#/) {
        print;
    } else {
        $_ =~ /^(.+?)\t(.+?)\t(.+?)\t(.+?)\t(.+?)\t/;
        $chrom = $1;
        $pos = $2;
        $tag = $3;
        $ref = $4;
        $alts = $5;
        $hasnonsnp = 0;
        $biallelic = 1;
        if ($alts =~ /,/) {
            $biallelic = 0;
        }
        @alts = split(/,/, $alts);
        foreach $alt (@alts) {
            if (!(length($alt)==1 && length($alt) == length($ref))) {
                $hasnonsnp = 1;
            }
        }
        if ($hasnonsnp || !$biallelic) {
            print;
        }
    }
}