N, K = gets.split.map(&:to_i)
as = gets.split.map(&:to_i).sort

MOD = 10**9+7
ans = 1
pt = 0
pool = 0
(N-1).downto(0) do |i|
    while pt < i && as[pt] + as[i] <= K
        pt += 1
        pool += 1
    end
    if pt == i
        pool += 1
        break
    end
    if pool == 0
        puts 0
        exit
    end
    ans = ans * pool % MOD
    pool -= 1
end
while pool > 0
    ans = ans * (pool - 1) % MOD
    pool -= 2
end
puts ans