#maspyさんのコード(https://yukicoder.me/submissions/602281)をもとにつくったO(N)解

def check(N,K,A):
    import itertools
    MOD = 998_244_353
    def is_balanced(A, Acum):
        for a, b in zip(A[1:], Acum[1:]):
            if a > b:
                return False
        return True

    def main(N, K, A):
        S = [0] + list(itertools.accumulate(A))
        if not is_balanced(A, S):
            return 0
        MAX = K + 10
        # x 以下の数列は対策済
        dp = [0] * (MAX + MAX + 1)
        v = A[-1] - 1
        res = 1
        for n in range(N - 2, -1, -1):
            print(v)
            if v < S[n] + A[n] - 1:
                low = A[n]
            else:
                low = -K
            #print(A[n]+1-low)
            res *= (A[n]+1-low)
            res %= MOD
            v = max(A[n]-1,v//2)

        return res

    return main(N,K,A)

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