n = int(input()); m = 10**5; mod = 998244353
a = list(map(int,input().split()))+[0]
dp = [1]*(m+1)
for i in range(n):
    eq = [0]*(m+1)
    for j in range(m+1):
        if j>=a[i]-a[i-1]: eq[j] = dp[j-max(a[i]-a[i-1],0)]
    for j in range(m): eq[j+1] = (eq[j+1]+eq[j])%mod
    dp = eq
print(dp[m])