n=int(eval(input()))



for i in range(n,0,-1):

  if float(i**0.5).is_integer():

    print(i)

    break
n=int(eval(input()))



for i in range(n,0,-1):

  if (i**0.5)%1==0:

    print(i)

    break
n = int(eval(input()))
for i in range(n, 0, -1):
    if float(i**0.5).is_integer():
        print(i)
        break

n = int(eval(input()))
for i in range(n, 0, -1):
    if (i**0.5) % 1 == 0:
        print(i)
        break

-    if float(i**0.5).is_integer(): +    if (i**0.5) % 1 == 0: