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 Ruby (2.3.3) (judge verdict: Accepted)

r, g, b, n = gets().split().map(&:to_i)

m = [r, g, b].sort

i = 0
j = 0
k = 0

c = 0

r0 = n - i * m[0]

loop do 
  j = 0
  g0 = r0 - j * m[1]
  loop do
    if g0 % m[2] == 0
      c += 1
    end

    j += 1
    g0 = r0 - j * m[1]
    break if g0 < 0
  end

  i += 1
  r0 = n - i * m[0]
  break if r0 < 0
end

puts c