my @lines;
open(IN1, '<', 'file1') or die $!;
while(my $line = <IN1>) { 
    chomp $line;
    push @lines, $line;
}
close(IN2);

open(IN2, '<', 'file2') or die $!;
while(my $line = <IN2>) { 
    chomp $line;
    push @lines, $line;
}
close(IN2);


my $size = scalar(@lines);   # Get the size of the array