L. Protecting The Earth
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

The earth is a coordinate plane and your job is to protect it.

Given $$$K$$$ (the number of people on earth), you have to make a sheild to protect them.

Find the minimum integer radius of a circle which is centered in the $$$(0,0)$$$ coordinates and can contain $$$K$$$ person knowing that a person can only stand on integer coordinates and two people can't stand in the same spot.

Note 1: A person can stand in the center of the circle.

Note 2: The person is considered protected if he's inside the cricle or at the boundary of the circle.

Input

The only line contains one integer $$$K$$$ ($$$ 2 \le K \le 10^9$$$) — the number of people on earth.

Output

Print one integer: the minimum integer circle radius that we need to protect all $$$K$$$ citizens of the earth.

Examples
Input
2
Output
1
Input
6
Output
2
Input
13
Output
2