Find the largest square number not exceeding N. Here, a square number is an integer that can be represented as the square of an integer.

Constraints

* 1 \leq N \leq 10^9
* N is an integer.

Input

Input is given from Standard Input in the following format:


N


Output

Print the largest square number not exceeding N.

Examples

Input

10


Output

9


Input

81


Output

81


Input

271828182


Output

271821169
import sys

DBG_FLAG = 0

def p_dbg(str):
    if(DBG_FLAG == 1):
        sys.stdout.flush()
        print str

# 1st. get Num

Num = int(raw_input())

p_dbg('Num : ' + str(Num))

square_max = 1

# MEMORY OVER
# for i in range(1, Num):
#     tmp = i * i
#     p_dbg(str(i) + str(square_max))
#     if(tmp <= Num):
#         square_max = tmp
#     else:
#         break

i = 1
tmp = 1
while tmp <= Num:
    p_dbg(str(i) + ':' + str(square_max))
    square_max = tmp
    tmp = i*i
    i = i+1

print square_max
