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: Wrong Answer)

const TEST = `2 1 1 3`
// A B C K

function Main(input) {
  const inputArr = input.trim().split(" ");
  console.log(inputArr)
  let countA = parseInt(inputArr[0])
  let countB = parseInt(inputArr[1])
  let countC = parseInt(inputArr[2])
  let countK = parseInt(inputArr[3])
  let res = 0
  for (let i = countK; i > 0; i--) {
    if (countA !== 0) {
      countA = countA - 1
      res = res + 1
    } else {
      countC = countC - 1
      res = res - 1
    }
  }
  console.log(res)
}

//*この行以降は編集しないでください（標準入出力から一度に読み込み、Mainを呼び出します）
Main(require("fs").readFileSync("/dev/stdin", "utf8"));