MOD = 998244353

def main():
    import sys
    input = sys.stdin.read().split()
    N = int(input[0])
    A = list(map(int, input[1:N+1]))
    
    total = 0
    for k in range(N):
        a_k = A[k]
        product = 1
        for j in range(N):
            if j == k:
                continue
            term = (A[j] * A[j] - a_k * a_k) % MOD
            product = (product * term) % MOD
        denominator = (a_k % MOD) * product % MOD
        if denominator == 0:
            print(0)
            return
        inv_denominator = pow(denominator, MOD-2, MOD)
        total = (total + inv_denominator) % MOD
    print(total)

if __name__ == "__main__":
    main()