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.
n=int(input())
from itertools import combinations

a = sorted(list(map(float, input().split())), reverse=True)

pre = [1]*100
pre[0] = 1 - a[0]
for i in range(1, n):
    pre[i] = pre[i-1] * (1-a[i])

ans = 0
for i in range(1,n+1):
    anss=0
    for j in range(i):
        anss += pre[i-1] / (1-a[j]) * a[j]
    ans = max(ans, anss)
print(ans)