MOD = 998244353

n = int(input())
A = list(map(int, input().split()))

a = [x % MOD for x in A]
a_sq = [(x * x) % MOD for x in a]

result = 0
for k in range(n):
    ak = a[k]
    ak_sq = a_sq[k]
    product = 1
    for i in range(n):
        if i == k:
            continue
        term = (a_sq[i] - ak_sq) % MOD
        product = (product * term) % MOD
    denominator = (ak * product) % MOD
    inv_denominator = pow(denominator, MOD-2, MOD)
    result = (result + inv_denominator) % MOD

print(result)