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.Generic;
using System.Linq;

class Progaram
{
    static void Main(string[] args)
    {
        var l = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
        var R = l[0]; var G = l[1]; var B = l[2]; var n = l[3];

        var res = 0;
        for (var r = 0; 3001 > r; r++)
            for (var g = 0; 3001 > g; g++)
            {
                var b = ((n - (r * R + g * G)) % B == 0 && n - (r * R + g * G) >= 0 || n - (r * R + g * G) == 0) ? (n - (r * R + g * G)) / B : -1;
                if (b == -1) continue;
                res++;
            }
        Console.WriteLine(res);
    }
}