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++14 (GCC 5.4.1) (judge verdict: Time Limit Exceeded)

#include <iostream>
#include <string>
using namespace std;

int main(){
  int R,G,B,N;
  int result = 0;
  cin >> R >> G >> B >> N ;
  int r1 = N/R + 1;
  for(int r = 0; r <= r1; ++r){
      for(int g = 0; R*r + G*g <= N; ++g){
          for(int b = 0; R*r + G*g + B*b <= N; ++b){
            if(N == R*r + G*g + B*b){++result;}      
          }
      }
  }
  cout << result << endl;
}