import numpy as np

N, K = map(int, input().split())
A = [int(x) - K for x in input().split()]

MOD = 10 ** 9 + 7
L = 10000
dp = np.zeros(2 * L + 1, dtype=int)
dp[L] = 1

for a in A:
    if a >= 0:
        dp[a:] += dp[:2 * L + 1 - a]
    else:
        dp[:a] += dp[-a:]
    dp %= MOD
print((sum(dp[L:]) - 1) % MOD)