Two Switches

AtCoder
IDabc070_b
Time2000ms
Memory256MB
Difficulty
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: $A$ $B$ $C$ $D$ [samples]
Samples
Input #1
0 75 25 100
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.
Input #2
0 33 66 99
Output #2
0

Alice and Bob were not holding their buttons at the same time, so the answer is zero seconds.
Input #3
10 90 20 80
Output #3
60
API Response (JSON)
{
  "problem": {
    "name": "Two Switches",
    "description": {
      "content": "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",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "abc070_b"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "Alice and Bob are controlling a robot. They each have one switch that controls the robot.  \nAlice started holding down her button $A$ second after the start-up of the robot, and released her button $B...",
      "is_translate": false,
      "language": "English"
    }
  ]
}
Full JSON Raw Segments