Problem:
Score : 200 points

Problem Statement

Alice and Bob are controlling a robot. They each have one switch that controls the robot.

Alice started holding down her button A second after the start-up of the robot, and released her button B second after the start-up.

Bob started holding down his button C second after the start-up, and released his button D second after the start-up.

For how many seconds both Alice and Bob were holding down their buttons?

Constraints

0≤A<B≤100

0≤C<D≤100

All input values are integers.

Input

Input is given from Standard Input in the following format:

A B C D

Output

Print the length of the duration (in seconds) in which both Alice and Bob were holding down their buttons.

Sample Input 1

0 75 25 100

Sample Output 1

50

Alice started holding down her button 0 second after the start-up of the robot, and released her button 75 second after the start-up.

Bob started holding down his button 25 second after the start-up, and released his button 100 second after the start-up.

Therefore, the time when both of them were holding down their buttons, is the 50 seconds from 25 seconds after the start-up to 75 seconds after the start-up.

Sample Input 2

0 33 66 99

Sample Output 2

0

Alice and Bob were not holding their buttons at the same time, so the answer is zero seconds.

Sample Input 3

10 90 20 80

Sample Output 3

60

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)



import java.io.*;
import java.util.*;

public class Main {
	static final int N=(int)5005;
    public static void main(String[] args) {  
        InputStream sys=System.in;
        InputReader in=new InputReader(sys);
        PrintWriter out=new PrintWriter(System.out);
        int A=in.nextInt(),B=in.nextInt();
        int C=in.nextInt(),D=in.nextInt();
        int ans=0;
        if(C>=B||A>=D) ans=0;
        else {
        	if(A>C) ans+=A-C;
        	else ans+=C-A;
        	if(B>D) ans+=B-D;
        	else ans+=D-B;
        }
        if(A<=C&&D<=B) ans=D-C;
        if(C<=A&&B<=D) ans=B-A;
        out.println(ans);
        out.flush();
    }
	static class InputReader {
		public BufferedReader reader;
		public StringTokenizer tokenizer;
        
		public InputReader(InputStream stream) {
			reader = new BufferedReader(new InputStreamReader(stream), 32768);
			tokenizer = null;
		}

		public String next() {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		}

		public int nextInt() {
			return Integer.parseInt(next());
		}
		
		public double nextDouble() {
			return Double.parseDouble(next());
		}
	}
}