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 Ruby (2.7.1) (judge verdict: Wrong Answer)

def main
  # min = ARGV[0].to_i
  # max = ARGV[1].to_i
  # multiple = ARGV[2].to_i
  min, max, multiple = gets.split(' ')
  min = min.to_i
  max = max.to_i
  multiple = multiple.to_i
  
  return puts 0 if multiple == 0
  min_multi = (min / multiple) * multiple
  min_multi = min_multi + multiple if min_multi == 0
  max_multi = (max / multiple) * multiple

  return puts 0 if max_multi == 0

  count = (max_multi - min_multi) / multiple + 1
  

  return puts count
end

main