#!/usr/bin/perl -w 
use strict; 

open(FH, "table") or die "Can't open file to read!: $!\n";

for my $i (2..682)  { 
  while (<FH>) { 
    chomp; 
    my @matrix = split; 
    my $seed = $matrix[$i];
    if ($seed !~ /[ACGTN-]/) {
      print "P$i ";
      last;
    }
  }
  seek FH, 0, 0;
}

close FH;