102610: [AtCoder]ABC261 A - Intersection

Problem Statement

We have a number line. Takahashi painted some parts of this line, as follows:

• First, he painted the part from $X=L_1$ to $X=R_1$ red.
• Next, he painted the part from $X=L_2$ to $X=R_2$ blue.

Find the length of the part of the line painted both red and blue.

Constraints

• $0\leq L_1<R_1\leq 100$
• $0\leq L_2<R_2\leq 100$
• All values in input are integers.

Input

Input is given from Standard Input in the following format:

$L_1$ $R_1$ $L_2$ $R_2$

Output

Print the length of the part of the line painted both red and blue, as an integer.

Sample Input 1

0 3 1 5

Sample Output 1

2

The part from $X=0$ to $X=3$ is painted red, and the part from $X=1$ to $X=5$ is painted blue.

Thus, the part from $X=1$ to $X=3$ is painted both red and blue, and its length is $2$.

Sample Input 2

0 1 4 5

Sample Output 2

0

No part is painted both red and blue.

Sample Input 3

0 3 3 7

Sample Output 3

0

If the part painted red and the part painted blue are adjacent to each other, the length of the part painted both red and blue is $0$.

问题描述

我们有一个数轴。高桥按照以下方式涂了一些部分：

• 首先，他将从$X=L_1$到$X=R_1$的部分涂成红色。
• 接下来，他将从$X=L_2$到$X=R_2$的部分涂成蓝色。

求线段中同时涂成红色和蓝色的部分的长度。

约束

• $0\leq L_1<R_1\leq 100$
• $0\leq L_2<R_2\leq 100$
• 输入中的所有值都是整数。

输入

从标准输入以以下格式获取输入：

$L_1$ $R_1$ $L_2$ $R_2$

输出

以整数形式打印线段中同时涂成红色和蓝色的部分的长度。

样例输入 1

0 3 1 5

样例输出 1

2

从$X=0$到$X=3$的部分涂成红色，从$X=1$到$X=5$的部分涂成蓝色。

因此，从$X=1$到$X=3$的部分同时涂成红色和蓝色，其长度为$2$。

样例输入 2

0 1 4 5

样例输出 2

0

没有部分同时涂成红色和蓝色。

样例输入 3

0 3 3 7

样例输出 3

0

如果涂成红色和涂成蓝色的部分相邻，则同时涂成红色和蓝色的部分的长度为$0$。