MOD = 998244353

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

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

sum_result = 0
for k in range(n):
    a_k = A[k]
    a_k_sq = a_sq[k]
    product = 1
    for i in range(n):
        if i != k:
            term = (a_sq[i] - a_k_sq) % MOD
            product = (product * term) % MOD
    d_k = (a_k * product) % MOD
    inv_dk = pow(d_k, MOD-2, MOD)
    sum_result = (sum_result + inv_dk) % MOD

print(sum_result)