MOD = 998244353

M = 10**5
n = int(input())
A = list(map(int, input().split()))

dp = [0] * (M + 1)
dp[0] = 1
b = 0
for a in A:
    for i in range(M):
        dp[i + 1] = (dp[i] + dp[i + 1]) % MOD
    add = max(0, b - a)
    dp = [0] * add + dp[: M + 1 - add]
    for i in range(M - a + 1, M + 1):
        dp[i] = 0

    b = a


print(sum(dp) % MOD)