MOD = 998244353

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

result = 0
for j in range(n):
    aj = A[j]
    denominator = aj
    valid = True
    for k in range(n):
        if k == j:
            continue
        term = (pow(A[k], 2, MOD) - pow(aj, 2, MOD)) % MOD
        denominator = (denominator * term) % MOD
        if denominator == 0:
            valid = False
            break
    if not valid:
        continue  # Skip if any term is zero (denominator is zero)
    inv_denominator = pow(denominator, MOD - 2, MOD)
    result = (result + inv_denominator) % MOD

print(result)