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.
import bisect
n=int(input())
ls=list(map(float,input().split()))
ls.sort()
mx=ls[-1]
idx=bisect.bisect_left(ls,0.5)
if idx<n and ls[idx]<0.5:
    idx+=1

res=0
st=0
while(st<idx-1):
    temp=0
    for i in range(st,idx):
        t=1
        for j in range(st,idx):
            if i!=j:
                t=t*(1-ls[j])
                
        temp+=t*ls[i]
    res=max(res,temp)
    st+=1
res=max(res,mx)
print("%.12f"%res)