N = int(eval(input()))

if N < 4:

  print((1))

  exit()

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

  if i**0.5 == int(i**0.5):

    print(i)

    exit()
N = int(eval(input()))

print((int(N**0.5)**2))
N = int(eval(input()))
if N < 4:
    print((1))
    exit()
for i in range(N, 1, -1):
    if i**0.5 == int(i**0.5):
        print(i)
        exit()

N = int(eval(input()))
print((int(N**0.5) ** 2))

-if N < 4: -    print((1)) -    exit() -for i in range(N, 1, -1): -    if i**0.5 == int(i**0.5): -        print(i) -        exit() +print((int(N**0.5) ** 2))