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.Text;
using System.Numerics;

namespace SolutionCS
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] inS = Console.ReadLine().Split(' ');
            int R = int.Parse(inS[0]);
            int G = int.Parse(inS[1]);
            int B = int.Parse(inS[2]);
            int N = int.Parse(inS[3]);

            int result = 0;

            for (int r = 0; r <= N; r += R)
            {
                for(int g = 0; r + g <= N; g+= G)
                {
                    int remain = N - r - g;

                    if ( remain % B == 0 )
                    {
                        result++;
                    }
                }
            }

            Console.WriteLine("{0}", result);
        }
    }
}