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;
using System.Text;
using System.Threading.Tasks;

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

            for (r = 0; r * R <= N; r++)
            {
                for (g = 0; g * G + r * R <= N; g++)
                {
                    if((N - g * G - r * R)%B == 0 || N == g * G + r * R) count++;
                }
            }

            Console.WriteLine(count);
        }

    }
}