# require 'prime'
loop do
    n, x = gets.split.map(&:to_i)
    # break if n == 0
    # a = (1..n).map { gets.to_i }.sort
    # t = Array.new(x + 1, false)
    # t[0] = true
    # (0..x).each do |i|
    #     next if !t[i]
    #     a.each do |j|
    #         break if i + j > x
    #         t[i + j] = true
    #     end
    # end
    # ans = nil
    # x.downto(1) do |i|
    #     if t[i] && Prime.prime?(i)
    #         ans = i
    #         break
    #     end
    # end
    puts ans ? ans : 'NA'
end

