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 Pascal (FPC 2.6.2) (judge verdict: Accepted)

var s,r,g,b,n,t:Longint;
begin
read(r,g,b,n);
if r<g then begin
	t:=r;
	r:=g;
	g:=t;
end;
if r<b then begin
	t:=r;
	r:=b;
	b:=t;
end;
if r=1 then begin
	t:=n;
	while t>=0 do begin
		inc(s,t div g+1);
		dec(t,b);
	end;
	writeln(s);
	exit;
end;
t:=n;
while True do begin
if t<0 then begin
dec(n,b);
t:=n;
if t<0 then begin
writeln(s);
exit;
end;
end;
if t mod r=0 then inc(s);
dec(t,g);
end;
end.