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 PHP (5.6.30) (judge verdict: Time Limit Exceeded)

<?php
list($r, $g, $b, $n) = explode(" ", fgets(STDIN));
$r_max = floor($n/$r);
$g_max = floor($n/$g);
$answer=0;
for($i=0; $i<=$r_max; $i++){
	for($i_2=0; $i_2<=$g_max; $i_2++){
		$check = ($n-$r*$i-$g*$i_2)/$b;
		if(is_int($check) && $check >=0){
			$answer +=1;
		}
	}
}
echo $answer;

?>