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

MOD = 998244353

ans = 0
for i in range(N):
    tmp = 1
    for k in range(N):
        if i == k:
            continue
        tmp = (tmp * (A[k] * A[k] - A[i] * A[i])) % MOD
    tmp %= MOD
    tmp = (tmp * A[i]) % MOD
    ans += pow(tmp, MOD - 2, MOD)
    ans %= MOD
print(ans)