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 static System.Console;
using static System.Math;

class Program
{
    static void Main()
    {
        var RGBN = ReadLine().Split().Select(int.Parse).ToArray();
        var R = RGBN[0];
        var G = RGBN[1];
        var B = RGBN[2];
        var N = RGBN[3];

        var a = 0;
        var I=N/R;
        for (int i = 0; i <= I; i++)
        {
            var J=(N-R*i)/G;
            for (int j = 0; j <= J; j++)
            {
                var m = N - i * R - j * G;
                if (m % B == 0) a++;
            }
        }

        WriteLine(a);
    }
}