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;
namespace inonoa{
    class Ino{
        static void Main(){
            string[] r_g_b_n = Console.ReadLine().Split();
            int r = int.Parse(r_g_b_n[0]);
            int g = int.Parse(r_g_b_n[1]);
            int b = int.Parse(r_g_b_n[2]);
            int n = int.Parse(r_g_b_n[3]);
            int ans = 0;
            for(int i=0;i<(n/r)+1;i++){
                for(int j=0;j<(n/g)+1;j++){
                    if((n - i*r - j*g)%b==0 && n-i*r-j*g>=0){
                        ans ++;
                    }
                }
            }
            Console.WriteLine(ans);
        }
    }
}