{
    local $_= <DATA>;
    while(  defined $_  ) {
        chomp;
        s/(.)G57/$1\nG57/g;
        print $1   if  s/(.*\n)//s;
        if(  ! /G5?$/  ) {
            print $_,$/   if  "" ne $_;
            $_= <DATA>;
        } else {
            my $next= <DATA>;
            last    unless  defined $next;
            $_ .= $next;
        }
    }
    print $_,$/;
}
__END__
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