MOD = 998_244_353

def main(N, K, A):
    S = [0] * (N+1)
    for i in range(N):
        S[i + 1] = S[i] + A[i]
    if any(a > b for a, b in zip(A[1:], S[1:])):
        return 0
    v = A[-1] - 1
    ans = 1
    for n in range(N - 2, -1, -1):
        s, a = S[n], A[n]
        if v < s + a - 1:
            pass
        else:
            ans = ans * (A[n] + K + 1) % MOD
        v = max(a - 1, v // 2)
    return res

N, K = map(int, input().split())
A = list(map(int, input().split()))
print(main(N, K, A))