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 C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>
 
int main(void){
	int i,temp,temp2;
	int a[4];

	for(i=0;i<4;i++){
	scanf("%d",&a[i]);
	}
 	
 	if(a[1] < a[3]) temp = a[1];
 	else temp = a[3];
	
	printf("%d\n",temp); 	

 	if(a[0] < a[2]) temp2 = a[2];
 	else temp2 = a[0];
 	printf("%d\n",temp2); 	

 	if(0 > temp - temp2)
 		printf("%d\n",0);
 	else
    printf("%d\n",temp - temp2);
	
	return 0;
}