After a drawn-out mooclear arms race, Farmer John and the Mischievous Mess Makers have finally agreed to establish peace. They plan to divide the territory of Bovinia with a line passing through at least two of the *n* outposts scattered throughout the land. These outposts, remnants of the conflict, are located at the points (*x*<sub class="lower-index">1</sub>, *y*<sub class="lower-index">1</sub>), (*x*<sub class="lower-index">2</sub>, *y*<sub class="lower-index">2</sub>), ..., (*x*<sub class="lower-index">*n*</sub>, *y*<sub class="lower-index">*n*</sub>).

In order to find the optimal dividing line, Farmer John and Elsie have plotted a map of Bovinia on the coordinate plane. Farmer John's farm and the Mischievous Mess Makers' base are located at the points *P* = (*a*, 0) and *Q* = ( - *a*, 0), respectively. Because they seek a lasting peace, Farmer John and Elsie would like to minimize the maximum difference between the distances from any point on the line to *P* and *Q*.

Formally, define the difference of a line <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/c7c068229f25f741e2c902b657ba04a42feb0752.png" style="max-width: 100.0%;max-height: 100.0%;"/> relative to two points *P* and *Q* as the smallest real number *d* so that for all points *X* on line <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/c7c068229f25f741e2c902b657ba04a42feb0752.png" style="max-width: 100.0%;max-height: 100.0%;"/>, |*PX* - *QX*| ≤ *d*. (It is guaranteed that *d* exists and is unique.) They wish to find the line <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/c7c068229f25f741e2c902b657ba04a42feb0752.png" style="max-width: 100.0%;max-height: 100.0%;"/> passing through two distinct outposts (*x*<sub class="lower-index">*i*</sub>, *y*<sub class="lower-index">*i*</sub>) and (*x*<sub class="lower-index">*j*</sub>, *y*<sub class="lower-index">*j*</sub>) such that the difference of <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/c7c068229f25f741e2c902b657ba04a42feb0752.png" style="max-width: 100.0%;max-height: 100.0%;"/> relative to *P* and *Q* is minimized.
The first line of the input contains two integers *n* and *a* (2 ≤ *n* ≤ 100 000, 1 ≤ *a* ≤ 10 000) — the number of outposts and the coordinates of the farm and the base, respectively.

The following *n* lines describe the locations of the outposts as pairs of integers (*x*<sub class="lower-index">*i*</sub>, *y*<sub class="lower-index">*i*</sub>) (|*x*<sub class="lower-index">*i*</sub>|, |*y*<sub class="lower-index">*i*</sub>| ≤ 10 000). These points are distinct from each other as well as from *P* and *Q*.
In the first sample case, the only possible line <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/c7c068229f25f741e2c902b657ba04a42feb0752.png" style="max-width: 100.0%;max-height: 100.0%;"/> is *y* = *x* - 1. It can be shown that the point *X* which maximizes |*PX* - *QX*| is (13, 12), with <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/d4f8c9a4f500c322cb3725c981acd02ebf8d8b35.png" style="max-width: 100.0%;max-height: 100.0%;"/>, which is <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/f488f414e882e7593bfa43cb26e56aaa8072b748.png" style="max-width: 100.0%;max-height: 100.0%;"/>.

In the second sample case, if we pick the points (0, 1) and (0,  - 3), we get <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/c7c068229f25f741e2c902b657ba04a42feb0752.png" style="max-width: 100.0%;max-height: 100.0%;"/> as *x* = 0. Because *PX* = *QX* on this line, the minimum possible difference is 0.
print("_RANDOM_GUESS_1692649102.4196646")# 1692649102.4196823