Score : 200 points
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.
Input is given from Standard Input in the following format:
N
Print the largest square number not exceeding N.
10
9
10 is not square, but 9 = 3 × 3 is. Thus, we print 9.
81
81
271828182
271821169