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: Wrong Answer)

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

using E = System.Linq.Enumerable;

public class Program
{
    public static void Main()
    {
        var agbn = Console.ReadLine().Split().Select(x => int.Parse(x)).ToArray();
        var a = agbn[0];
        var g = agbn[1];
        var b = agbn[2];
        var n = agbn[3];

        var k = 0;
        var m = 0;
        for (int i = 0; m <= n; i++)
        {
            var ai = a * i;
            for (int j = 0; m <= n; j++)
            {
                m = ai + g * j;
                if ((n - m) % b != 0)
                {
                    continue;
                }

                k++;
            }
            m = ai;
        }
        Console.WriteLine(k);
    }
}