MOD = 998244353

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

if __name__ == '__main__':
    main()