Codeforces Round 528 (Div. 1, based on Technocup 2019 Elimination Round 4)
F
Forest Fires
Codeforces
3500
原题
← E→
翻译中…

Berland forest was planted several decades ago in a formation of an infinite grid with a single tree in every cell. Now the trees are grown up and they form a pretty dense structure.

翻译中…

So dense, actually, that the fire became a real danger for the forest. This season had been abnormally hot in Berland and some trees got caught on fire!

翻译中…

The second fire started is considered the second $0$. Every second fire lit up all intact neightbouring trees to every currently burning tree. The tree is neighbouring if it occupies adjacent by side or by corner cell. Luckily, after $t$ seconds Berland fire department finally reached the location of fire and instantaneously extinguished it all.

翻译中…

Now they want to calculate the destructive power of the fire. Let $val_{x, y}$ be the second the tree in cell $(x, y)$ got caught on fire. The destructive power is the sum of $val_{x, y}$ over all $(x, y)$ of burnt trees.

翻译中…

Clearly, all the workers of fire department are firefighters, not programmers, thus they asked you to help them calculate the destructive power of the fire.

翻译中…

The result can be rather big, so print it modulo $998244353$.

翻译中…

Input

翻译中…

The first line contains two integers $n$ and $t$ ($1 \le n \le 50$, $0 \le t \le 10^8$) — the number of trees that initially got caught on fire and the time fire department extinguished the fire, respectively.

翻译中…

Each of the next $n$ lines contains two integers $x$ and $y$ ($-10^8 \le x, y \le 10^8$) — the positions of trees that initially got caught on fire.

翻译中…

Obviously, the position of cell $(0, 0)$ on the grid and the directions of axes is irrelevant as the grid is infinite and the answer doesn't depend on them.

翻译中…

It is guaranteed that all the given tree positions are pairwise distinct.

翻译中…

The grid is infinite so the fire doesn't stop once it reaches $-10^8$ or $10^8$. It continues beyond these borders.

翻译中…

Output

翻译中…

Print a single integer — the sum of $val_{x, y}$ over all $(x, y)$ of burnt trees modulo $998244353$.

翻译中…

Note

翻译中…

Here are the first three examples. The grey cells have $val = 0$, the orange cells have $val = 1$ and the red cells have $val = 2$.

翻译中…

image

翻译中…

样例

Input #1
1 2
10 11
Output #1
40
InputCopy OutputCopy
Input #2
4 1
2 2
1 3
0 2
2 4
Output #2
18
InputCopy OutputCopy
Input #3
3 0
0 0
-2 1
1 1
Output #3
0
InputCopy OutputCopy
题目信息
题号
1086F
时间限制
2.5 s
内存限制
256 MB
标签
数学

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。