output_description: Print the largest square number not exceeding N.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
attempt: # region header
  import sys
  import math
  from bisect import bisect_left, bisect_right, insort_left, insort_right
  from collections import defaultdict, deque, Counter
  from copy import deepcopy
  from fractions import gcd
  from functools import lru_cache, reduce
  from heapq import heappop, heappush
  from itertools import (
      accumulate,
      groupby,
      product,
      permutations,
      combinations,
      combinations_with_replacement,
  )
  from math import ceil, floor, factorial, log, sqrt, sin, cos
  from operator import itemgetter
  from string import ascii_lowercase, ascii_uppercase, digits
  
  sys.setrecursionlimit(10**7)
  rs = lambda: sys.stdin.readline().rstrip()
  ri = lambda: int(rs())
  rf = lambda: float(rs())
  rs_ = lambda: [_ for _ in rs().split()]
  ri_ = lambda: [int(_) for _ in rs().split()]
  rf_ = lambda: [float(_) for _ in rs().split()]
  INF = float("inf")
  MOD = 10**9 + 7
  PI = math.pi
  # endregion
  N = ri()
  print(floor(sqrt(N)) ** 2)
  
problem_description: Statement
  
  Find the largest square number not exceeding N. Here, a _square number_ is an
  integer that can be represented as the square of an integer.
samples: [{"input": "10", "output": "9\n    \n\n10 is not square, but 9 = 3 \u00d7 3 is. Thus, we print 9.\n\n* * *"}, {"input": "81", "output": "81\n    \n\n* * *"}, {"input": "271828182", "output": "271821169"}]