Andrey needs one more problem to conduct a programming contest. He has *n* friends who are always willing to help. He can ask some of them to come up with a contest problem. Andrey knows one value for each of his fiends — the probability that this friend will come up with a problem if Andrey asks him.

Help Andrey choose people to ask. As he needs only one problem, Andrey is going to be really upset if no one comes up with a problem or if he gets more than one problem from his friends. You need to choose such a set of people that maximizes the chances of Andrey not getting upset.
The first line contains a single integer *n* (1 ≤ *n* ≤ 100) — the number of Andrey's friends. The second line contains *n* real numbers *p*<sub class="lower-index">*i*</sub> (0.0 ≤ *p*<sub class="lower-index">*i*</sub> ≤ 1.0) — the probability that the *i*-th friend can come up with a problem. The probabilities are given with at most 6 digits after decimal point.

if __name__ == '__main__':
	N = int(input())
	probs = list(map(float, input().split()))
	probs.sort()
	P, S = 1.0, 0.0
	sol = 0.0
	for n in reversed(range(N)):
		# print(probs[n])
		if S > 1:
			# print(S + (probs[n]/(1 - probs[n])))
			break
		P, S = P*(1 - probs[n]), S + probs[n]/(1 - probs[n])
		# print(P, S, P*S)
		sol = P*S
	print(sol)