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: Accepted)

#include<iostream>
using namespace std;
int main()
{
	int r, g, b, n;
	int R, G, B;
	int left, mid, ans = 0;
	int i, j;
	cin >> r >> g >> b >> n;

	for (left = 0; left <= n; left++) {
		for (mid = 0; left+mid <= n; mid++) {
			R = left;
			G = mid;
			B = n - left - mid;
			if (R%r == 0 && G%g == 0 && B%b == 0) {
				ans++;
			}
		}
	}

	cout << ans << endl;
	return 0;

}