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: Accepted)

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

public class Hello
{
    public static void Main()
    {
        var list = Console.ReadLine().Split(' ');
        var r = int.Parse(list[0]);
        var g = int.Parse(list[1]);
        var b = int.Parse(list[2]);
        var n = int.Parse(list[3]);

        int count = 0;

        for (int rn = 0; rn <= n; rn += r)
        {
            var rest = n - rn;
            for (int gn = 0; gn <= rest; gn += g)
            {
                var bn = rest - gn;
                if (bn % b == 0)
                    ++count;
            }
        }

        Console.WriteLine(count);
    }
}