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 = input().split(" ")
    
    probs = [float(i) for i in probs]
    probs.sort(reverse=True)
    
    total = 0
    p = 1
    sol = 0
    
    for i in range(n):
        total += probs[i] / (1.0 - probs[i])
        p *= (1-probs[i])
        sol = max(sol, total*p)
        if (total > 1.0):
            break
    
    print(sol)
		    		        	     	      	