Problem:
Score : 200 points

Problem 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.

Constraints

1 \leq N \leq 10^9

N is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print the largest square number not exceeding N.

Sample Input 1

10

Sample Output 1

9

10 is not square, but 9 = 3 × 3 is. Thus, we print 9.

Sample Input 2

81

Sample Output 2

81

Sample Input 3

271828182

Sample Output 3

271821169

Solution in Python (3.4.3) (judge verdict: Wrong Answer)

import math
def Main():
    N = int(input())
    lists = []
    for i in range(N):
        lists.append(math.sqrt(i+1))
        if i == N-1:
            print(int(math.sqrt(i+1)**2))

    #lists.sort()
    #print(int(lists[len(lists)-1]**2))


if __name__ == "__main__":
    Main()