N,K = map(int,input().split())
A = list(map(int,input().split()))
P = 10 ** 9 + 7

C = 10 ** 4 * 2 + 1
base = 10 ** 4
dat = [0] * C
dat[base] = 1
for a in A:
    nx = dat.copy()
    a -= K
    for i in range(C):
        if 0 <= i + a < C:
            nx[i + a] += dat[i]
            nx[i + a] %= P
    dat = nx
ans = 0
for i in range(base,C):
    ans += dat[i]
    ans %= P
print((ans-1) % P)