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 C# (Mono 4.6.2.0) (judge verdict: Time Limit Exceeded)

using System;
using System.Linq;
using System.Collections.Generic;

class Program {
  static void Main(string[] args) {
    var rgbn = Console.ReadLine().Split(' ').Select(e => int.Parse(e)).ToArray();
    int r = rgbn[0], g = rgbn[1], b = rgbn[2], n = rgbn[3];

    int ans = 0;

    for (int i = 0; i <= n; i += r) {
      for (int j = 0; i + j <= n; j += g) {
        for (int k = 0; i + j + k <= n; k += b) {
          if (i + j + k == n) {
            ans++;
          }
        }
      }
    }

    Console.WriteLine(ans);
  }
}