MOD = 1000000007

H, W = map(int, input().split())

fact = [ 0 ] * (H + 1)
fact[0] = 1
for i in range(H):
	fact[i + 1] = fact[i] * (i + 1) % MOD
factinv = [ 0 ] * (H + 1)
factinv[H] = pow(fact[H], MOD - 2, MOD)
for i in range(H - 1, -1, -1):
	factinv[i] = factinv[i + 1] * (i + 1) % MOD

answer = 0
power2 = 1
for i in range(H, -1, -1):
	subanswer = pow(MOD - power2 + 1, W, MOD)
	comb = fact[H] * factinv[i] * factinv[H - i]
	if (i + W) % 2 == 0:
		answer += comb * subanswer
	else:
		answer -= comb * subanswer
	power2 = power2 * 2 % MOD

print(answer % MOD)