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;

namespace B
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] vs = RArInt();
            int r = vs[0];
            int g = vs[1];
            int b = vs[2];
            int n = vs[3];

            int res = 0;
            for (int i = 0; i <= n; i += r)
            {
                for (int j = 0; j <= n; j += g)
                {
                    if (i + j <= n && (n - (i + j)) % b == 0) res++;
                }
            }

            Console.WriteLine(res);
        }
        static string RSt() { return Console.ReadLine(); }
        static int RInt() { return int.Parse(Console.ReadLine().Trim()); }
        static long RLong() { return long.Parse(Console.ReadLine().Trim()); }
        static double RDouble() { return double.Parse(Console.ReadLine()); }
        static string[] RArSt(char sep = ' ') { return Console.ReadLine().Trim().Split(sep); }
        static int[] RArInt(char sep = ' ') { return Array.ConvertAll(Console.ReadLine().Trim().Split(sep), e => int.Parse(e)); }
        static long[] RArLong(char sep = ' ') { return Array.ConvertAll(Console.ReadLine().Trim().Split(sep), e => long.Parse(e)); }
        static double[] RArDouble(char sep = ' ') { return Array.ConvertAll(Console.ReadLine().Trim().Split(sep), e => double.Parse(e)); }
        static string WAr<T>(IEnumerable<T> array, string sep = " ") { return string.Join(sep, array.Select(x => x.ToString()).ToArray()); }
    }
}