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 (Clang 3.8.0) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>

int
desc(const void *a, const void *b)
{
        return *(int *)b - *(int *)a;
}

int
main(void)
{
        int RGB[3];
        int N;

        scanf("%d %d %d %d", &RGB[0], &RGB[1], &RGB[2], &N);
        qsort(RGB, sizeof(RGB) / sizeof(int), sizeof(int), desc);

        int count = 0;
        for (int i = 0; i <= N / RGB[0]; i++) {
                for (int j = 0; j <= N / RGB[1]; j++) {
                        int val = RGB[0] * i + RGB[1] * j;
                        if (val > 0 && (N - val) >= 0 && ((N - val) % RGB[2]) == 0)
                                count++;
                }
        }

        printf("%d", count);
}