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 PHP7 (7.0.15) (judge verdict: Wrong Answer)

<?php
$count = 0;
fscanf(STDIN,"%d %d %d %d",$a[0],$a[1],$a[2],$a[3]);
for ($i=0; $i < 3; $i++) { 
  $result[$i] = $d / $a[$i];
  if(is_int($result[$i])){
    ++$count;
}
}
if($a[0] + $a[1] == $a[3]){
++$count;
}
if($a[0] + $a[2] == $a[3]){
++$count;
}
if($a[1] + $a[2] == $a[3]){
++$count;
}
echo $count;