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 Diverta2910_B
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] strs = Console.ReadLine().Split();
            int r = int.Parse(strs[0]);
            int g = int.Parse(strs[1]);
            int b = int.Parse(strs[2]);
            int n = int.Parse(strs[3]);

            int _3, _2, _1;

            if (r > g && r > b)
            {
                _3 = r;

                if (g > b)
                {
                    _2 = g;
                    _1 = b;
                }
                else
                {
                    _2 = b;
                    _1 = g;
                }
            }
            else if (g > r && g > b)
            {
                _3 = g;
                if (r > b)
                {
                    _2 = r;
                    _1 = b;
                }
                else
                {
                    _2 = b;
                    _1 = r;
                }
            }
            else
            {
                _3 = b;
                if (r > g)
                {
                    _2 = r;
                    _1 = g;
                }
                else
                {
                    _2 = g;
                    _1 = r;
                }
            }

            int count = 0;

            for (int i = 0; i <= n; i += _3)
            {
                for (int j = i; j <= n; j += _2)
                {
                    if ((n - j) % _1 == 0) { ++count; }
                }

            }

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