MOD = 10 ** 9 + 7

from collections import defaultdict

n, k = map(int, input().split())
a = list(map(int, input().split()))

dp = defaultdict(int)
dp[0] = 1
for i in range(n):
  ndp = defaultdict(int)
  for x, v in dp.items():
    ndp[x] = (ndp[x] + v) % MOD
    ndp[x + a[i] - k] = (ndp[x + a[i] - k] + v) % MOD

  dp = ndp

ans = 0
for x, v in dp.items():
	if x >= 0:
		ans = (ans + v) % MOD

ans -= 1
print(ans)