MOD = 998244353

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

result = 0

for k in range(n):
    ak = a[k]
    denominator_part = 1
    for j in range(n):
        if j == k:
            continue
        aj = a[j]
        term = (aj * aj) % MOD
        term = (term - (ak * ak) % MOD) % MOD
        denominator_part = (denominator_part * term) % MOD
    denominator = (ak % MOD) * denominator_part % MOD
    inv_denominator = pow(denominator, MOD - 2, MOD)
    result = (result + inv_denominator) % MOD

print(result)