use strict;
use warnings;

my %hash = (
	N1 => { A => 1, B => 1},
	N2 => { A => 1, B => 1},
	N3 => { A => 1, B => 1},
	N6 => { A => 1, B => 1},
	N7 => { A => 1, B => 1},
);

# usage e.g. 
print $hash{N3}{A}, "\n";