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;

namespace AtCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            string input = Console.ReadLine();
            string[] input_num = input.Split(' ');
            int R = int.Parse(input_num[0]);
            int G = int.Parse(input_num[1]);
            int B = int.Parse(input_num[2]);
            int N = int.Parse(input_num[3]);
            // 愚直に実行してみる
            int r = 0, g = 0, b = 0, m = 0;
            int r_max = (N / R) + 1;
            int g_max = (N / G) + 1;
            int b_max = (N / B) + 1;

            if (N % r_max == 0)
            {
                m++;
                r_max--;
            }
            if (N % g_max == 0)
            {
                m++;
                g_max--;
            }
            if (N % b_max == 0)
            {
                m++;
                b_max--;
            }

            for (r = 0; r < r_max; r++)
            {
                for (g = 0; g < g_max; g++)
                {
                    for (b = 0; b < b_max; b++)
                    {
                        if ((r * R + g * G + b * B) == N) m++;
                    }
                }
            }
            Console.WriteLine(m.ToString());
        }
    }
}