MOD = 998244353

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

result = 0
for i in range(n):
    ai = a[i]
    term = 1
    for j in range(n):
        if i == j:
            continue
        aj = a[j]
        denominator = (ai * ai - aj * aj) % MOD
        if denominator == 0:
            print(0)
            exit()
        inv_denominator = pow(denominator, MOD-2, MOD)
        term = term * inv_denominator % MOD
    inv_ai = pow(ai, MOD-2, MOD)
    term = term * inv_ai % MOD
    result = (result + term) % MOD

# Multiply by (-1)^(n-1)
sign = pow(-1, n-1, MOD)
result = result * sign % MOD

print(result)