Problem:
Score : 100 points

Problem Statement

How many multiples of d are there among the integers between L and R (inclusive)?

Constraints

All values in input are integers.

1 \leq L \leq R \leq 100

1 \leq d \leq 100

Input

Input is given from Standard Input in the following format:

L R d

Output

Print the number of multiples of d among the integers between L and R (inclusive).

Sample Input 1

5 10 2

Sample Output 1

3

Among the integers between 5 and 10, there are three multiples of 2: 6, 8, and 10.

Sample Input 2

6 20 7

Sample Output 2

2

Among the integers between 6 and 20, there are two multiples of 7: 7 and 14.

Sample Input 3

1 100 1

Sample Output 3

100

Solution in Common Lisp (SBCL 2.0.3) (judge verdict: Accepted)

(setq l (read))
(setq r (read))
(setq d (read))
(prog (ans now)
  (setq ans 0)
  (setq now l)
  loop
  (cond ((> now r) (princ ans) (return ans)))
  (cond ((equal 0 (mod now d)) (setq ans (+ 1 ans))))
  (setq now (+ now 1))
  (go loop)
)