# LCS - Longest Common Substring

## 题意翻译

输入两个字符串，输出它们的最长公共子串长度，若不存在公共子串则输出 $0$。
其中字符串长度不超过 $2.5\times 10^5$。

## 题目描述

A string is finite sequence of characters over a non-empty finite set Σ.
In this problem, Σ is the set of lowercase letters.
Substring, also called factor, is a consecutive sequence of characters occurrences at least once in a string.
Now your task is simple, for two given strings, find the length of the longest common substring of them.
Here common substring means a substring of two or more strings.

## 输入输出格式

### 输入格式

The input contains exactly two lines, each line consists of no more than 250000 lowercase letters, representing a string.

### 输出格式

The length of the longest common substring. If such string doesn't exist, print "0" instead.

## 输入输出样例

### 输入样例 #1

```
alsdfkjfjkdsal
fdjskalajfkdsla
```

### 输出样例 #1

`3`