# coding: utf-8

N = int(eval(input()))

for i in range(1,N+1):

    if N == 1:

        print((1))

        break

    if i**2 > N:

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

        break
# coding: utf-8

import math

N = int(eval(input()))

n = int(math.sqrt(N))

print((n ** 2))
# coding: utf-8
N = int(eval(input()))
for i in range(1, N + 1):
    if N == 1:
        print((1))
        break
    if i**2 > N:
        print(((i - 1) ** 2))
        break

# coding: utf-8
import math

N = int(eval(input()))
n = int(math.sqrt(N))
print((n**2))

+import math + -for i in range(1, N + 1): -    if N == 1: -        print((1)) -        break -    if i**2 > N: -        print(((i - 1) ** 2)) -        break +n = int(math.sqrt(N)) +print((n**2))