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B - Around Square

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 $N$.

10

9

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

81

81

271828182

271821169