P, K = gets.split.map(&:to_i)
MOD = 10 ** 9 + 7
dp = Array.new(K + 2) { Array.new(2, 0) }
dp[0][0] = 1

K.times do |i|
  # zero * num
  dp[i + 1][0] += P * dp[i][0]
  # zero + non zero
  dp[i + 1][1] += (P - 1) * dp[i][0]
  # (non zero + zero)
  dp[i + 1][0] += dp[i][0]

  # non zero * zero
  dp[i + 1][0] += dp[i][1]
  # (non zero + non zero) % K == 0
  dp[i + 1][0] += dp[i][1]
  # (non zero + num) % K != 0
  dp[i + 1][1] += (P - 1) * dp[i][1]
  # (non zero * num) % K != 0
  dp[i + 1][1] += (P - 1) * dp[i][1]

  dp[i + 1][0] %= MOD
  dp[i + 1][1] %= MOD
end

puts dp[K][0]