import sys

N=eval(input())



for i in range(100000):

	if i*i==N:

		print(i*i)

		sys.exit()		

	elif i*i>N:

		print((i-1)*(i-1))

		sys.exit()

	else:

		continue

	

	
import math

N=eval(input())

print(int(math.sqrt(N))*int(math.sqrt(N)))
import sys

N = eval(input())
for i in range(100000):
    if i * i == N:
        print(i * i)
        sys.exit()
    elif i * i > N:
        print((i - 1) * (i - 1))
        sys.exit()
    else:
        continue

import math

N = eval(input())
print(int(math.sqrt(N)) * int(math.sqrt(N)))

-import sys +import math -for i in range(100000): -    if i * i == N: -        print(i * i) -        sys.exit() -    elif i * i > N: -        print((i - 1) * (i - 1)) -        sys.exit() -    else: -        continue +print(int(math.sqrt(N)) * int(math.sqrt(N)))