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.

Examples

Input

10

Output

9

Input

81

Output

81

Input

271828182

Output

271821169

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