Problem:
Score : 200 points

Problem Statement

Find the sum of the integers between 1 and N (inclusive), whose sum of digits written in base 10 is between A and B (inclusive).

Constraints

1 \leq N \leq 10^4

1 \leq A \leq B \leq 36

All input values are integers.

Input

Input is given from Standard Input in the following format:

N A B

Output

Print the sum of the integers between 1 and N (inclusive), whose sum of digits written in base 10 is between A and B (inclusive).

Sample Input 1

20 2 5

Sample Output 1

84

Among the integers not greater than 20, the ones whose sums of digits are between 2 and 5, are: 2,3,4,5,11,12,13,14 and 20. We should print the sum of these, 84.

Sample Input 2

10 1 2

Sample Output 2

13

Sample Input 3

100 4 16

Sample Output 3

4554

Solution in Ruby (2.3.3) (judge verdict: Accepted)

N,A,B = gets.split(" ").map(&:to_i)

res = 0
val = 0
cal = 0
dig = Math.log10(N).to_i

for n in 1..N
  data = n
  # 各桁の値を取得
  (0..dig).reverse_each do |i|
    cal = data / 10**i
    val += cal
    data = n % 10**i
  end

  if val >= A && B >= val then
    res += n
  end
  val = 0
end
puts res