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;
class Program
{
    static void Main(string[] args)
    {
        string[] input = Console.ReadLine().Split(' ');
        int[] Box = new int[3]
        {
            int.Parse(input[0]),
            int.Parse(input[1]),
            int.Parse(input[2])
        };
        int N = int.Parse(input[3]);
        Array.Sort(Box);
        int uCount = N / Box[2];
        int mCount = N / Box[1];
        int bCount = N / Box[0];

        int ans = 0;
        for(int i = 0; i <= uCount; i++)
        {
            int uv = Box[2] * i;
            mCount = (N - uv) / Box[1];
            for(int j = 0; j <= mCount; j++)
            {
                int mv = Box[1] * j;
                bCount = (N - mv) / Box[0];
                for(int k = 0; k <= bCount; k++)
                {
                    if (uv + mv + Box[0] * k == N)
                        ans++;
                }
            }
        }
        Console.WriteLine(ans);
    }
}