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: Wrong Answer)

using System;
using System.Linq;
using System.Threading.Tasks;
using static System.Console;
using static System.Math;
class program{
  static void Main(string[] args){
    program p = new program();
    p.Run();
  }
  void Run(){
	int[] inp = Readint();
    int R = inp[0];
    int G = inp[1];
    int B = inp[2];
    int N = inp[3];
    int c=0;
    Parallel.For(0,R,r=>{
      Parallel.For(0,G,g=>{
        if(N-r-g<=B & N-r-g>=0){
          c++;
        }
      });
    });
    WriteLine(c.ToString());
  }

  int[] Readint(){
    string[] s = ReadLine().Split();
    int[] res=new int[s.Length];
    Parallel.For(0,s.Length,i=>{
      res[i]=int.Parse(s[i]);
    });
    return res;
  }
}