use strict;
use warnings;
use Data::Dumper qw(Dumper);

my $filea = "FileA";
my $fileb = "FileB";

open ( FA, '<', $filea) || die ( "File $filea Not Found!" );
open ( FB, '<', $fileb) || die ( "File $fileb Not Found!" );

my %ts;
while ( <FB> ) {
    chomp;
    my($ids, $timestamp) = split ",";
    push @{ $ts{$timestamp} }, $ids;
}

while ( <FA> ) {
    chomp;
    my($life,$timestamp,$cls,$bool,$tot) = split ",";
    print STDERR "Loop tot-> $tot"; scalar <STDIN>;
    foreach ( 1 .. $tot ) {
        my $id = shift @{ $ts{$timestamp} };
        print join(",",$life, $id, $cls )."\n";
    }
}