Given an array a1, a2, ..., an of n integers, find the largest number in the array that is not a perfect square.

A number x is said to be a perfect square if there exists an integer y such that x = y2.

Input

The first line contains a single integer n (1 ≤ n ≤ 1000) — the number of elements in the array.

The second line contains n integers a1, a2, ..., an ( - 106 ≤ ai ≤ 106) — the elements of the array.

It is guaranteed that at least one element of the array is not a perfect square.

Output

Print the largest number in the array which is not a perfect square. It is guaranteed that an answer always exists.

Examples

Input

2
4 2


Output

2


Input

8
1 2 4 8 16 32 64 576


Output

32

Note

In the first sample case, 4 is a perfect square, so the largest number in the array that is not a perfect square is 2.
from math import sqrt
p1 = input()
p2 = raw_input().split(" ")
a = []
list = []
flag = 0
a = p2
a = [int(i) for i in a if i==str(i)]
a.sort(reverse = True)
j = []
for i in a:
  if i<0:
    list.append(i)
  else:
    r = sqrt(i)
    j.append(r)
if len(j)>0 or len(list)>0:
  for t,i in enumerate(j):
    if flag == 1:
      break
    p = len(str(i))
    if "." in str(i):
      lol = str(i).index(".")   
      if p-lol>2:
        list.append(a[t])
        flag = 1
      #print a[t] 
        break
    j.sort(reverse = True)  
    for i in j:
      if i<0:
        flag = 1
  print max(list), 
  #break
  """if flag == 0:
    print -1,"here"   """
else:
  print -1