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# (.NET Core 3.1.201) (judge verdict: Accepted)

using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.IO.Compression;
using System.Linq;
using System.Numerics;
using System.Runtime.CompilerServices;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Text.RegularExpressions;
using Console = System.Console;

namespace Atcoder
{

    class Program
    {
        private const long COMDIV = 1000000007;

        static void Main(string[] args)
        {
            var RGBN = Console.ReadLine().Split().Select(double.Parse).ToArray();
            var R = RGBN[0];
            var G = RGBN[1];
            var B = RGBN[2];
            var N = RGBN[3];

            int ret = 0;
            for (double r = 0; r <= 3000; r++)
            {
                for (double g = 0; g <= 3000; g++)
                {
                    var b = (N - r * R - g * G) / B;
                    var tran = b - Math.Truncate(b);
                    if (b < 0)
                    {
                        break;
                    }
                    if (tran == 0)
                    {
                        ret++;
                    }
                } 
            }

            Console.WriteLine(ret);
        }
    }
}