Problem:
Score : 200 points

Problem Statement

We have A cards, each of which has an integer 1 written on it. Similarly, we also have B cards with 0s and C cards with -1s.

We will pick up K among these cards. What is the maximum possible sum of the numbers written on the cards chosen?

Constraints

All values in input are integers.

0 \leq A, B, C

1 \leq K \leq A + B + C \leq 2 \times 10^9

Input

Input is given from Standard Input in the following format:

A B C K

Output

Print the maximum possible sum of the numbers written on the cards chosen.

Sample Input 1

2 1 1 3

Sample Output 1

2

Consider picking up two cards with 1s and one card with a 0.
In this case, the sum of the numbers written on the cards is 2, which is the maximum possible value.

Sample Input 2

1 2 3 4

Sample Output 2

0

Sample Input 3

2000000000 0 0 2000000000

Sample Output 3

2000000000

Solution in JavaScript (Node.js 12.16.1) (judge verdict: Accepted)

'use strict'

const Main = (input) => {
  const tmp = input.trim().split(' ')
  const A = parseInt(tmp[0])
  const B = parseInt(tmp[1])
  const C = parseInt(tmp[2])
  let K = parseInt(tmp[3])

  let ans = 0

  if (K - A >= 0) {
    K = K - A
    ans += 1 * A
  } else if (K - A < 0) {
    ans += 1 * K
    K = 0
  }

  if (K != 0 && (K - B) >= 0) {
    K = K - B
  } else if (K != 0 && (K - B) < 0) {
    K = 0
  }

  if (K != 0 && (K - C) >= 0) {
    K = K - C
    ans -= (1 * C)
  } else if (K != 0 && (K - C) < 0) {
    ans -= (1 * K)
  }

  let result = ans

  console.log(result)
  return result
}

Main(require('fs').readFileSync('/dev/stdin', 'utf8'))