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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int R = scan.nextInt();
        int G = scan.nextInt();
        int B = scan.nextInt();
        int N = scan.nextInt();
        int answer = 0;
        int max_r = N / R;
        int max_g = N / G;
        int max_b = N / B;
        for (int r = 0; r <= max_r; r++) {
            for (int g = 0; g <= max_g; g++) {
                if (N < r * R + g * G) {
                    continue;
                }
                int remain = N - r * R - g * G;
                if (remain % B != 0) {
                    continue;
                }
                if (remain / B <= max_b) {
                    answer += 1;
                }
            }
        }
        System.out.println(answer);
    }
}