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 Ruby (2.7.1) (judge verdict: Accepted)

# Your code here!

n = gets.chomp.to_i
i = 0
arr = []
while true
      
    if i ** 2 <= n
        arr << i ** 2
    else
        break
    end
    i += 1
end
puts arr.pop