import math

n = int(eval(input()))

for i in reversed(list(range(n+1))):

  if math.sqrt(i) - math.floor(math.sqrt(i)) == 0:

    print(i)

    exit()
n = int(eval(input()))

for i in range(n+2):

  if i**2 > n:

    print(((i-1)**2))

    exit()
import math

n = int(eval(input()))
for i in reversed(list(range(n + 1))):
    if math.sqrt(i) - math.floor(math.sqrt(i)) == 0:
        print(i)
        exit()

n = int(eval(input()))
for i in range(n + 2):
    if i**2 > n:
        print(((i - 1) ** 2))
        exit()

-import math - -for i in reversed(list(range(n + 1))): -    if math.sqrt(i) - math.floor(math.sqrt(i)) == 0: -        print(i) +for i in range(n + 2): +    if i**2 > n: +        print(((i - 1) ** 2))