Problem:
Score : 200 points

Problem Statement

Snuke has come to a store that sells boxes containing balls. The store sells the following three kinds of boxes:

Red boxes, each containing R red balls

Green boxes, each containing G green balls

Blue boxes, each containing B blue balls

Snuke wants to get a total of exactly N balls by buying r red boxes, g green boxes and b blue boxes.
How many triples of non-negative integers (r,g,b) achieve this?

Constraints

All values in input are integers.

1 \leq R,G,B,N \leq 3000

Input

Input is given from Standard Input in the following format:

R G B N

Output

Print the answer.

Sample Input 1

1 2 3 4

Sample Output 1

4

Four triples achieve the objective, as follows:

(4,0,0)

(2,1,0)

(1,0,1)

(0,2,0)

Sample Input 2

13 1 4 3000

Sample Output 2

87058

Solution in JavaScript (node.js v5.12) (judge verdict: Accepted)

'use strict';

function main(stdin) {
  const input = stdin.split(' ').map(v => { return parseInt(v, 10) });
  const R = input[0];
  const G = input[1];
  const B = input[2];
  const N = input[3];

  let ans = 0;

  for (let r = 0; r <= N; r += R) {
    for (let g = 0; g <= N - r; g += G) {
      if ((N - r - g) % B === 0) ++ans;
    }
  }

  console.log(ans);
}

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