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 OCaml (4.02.3) (judge verdict: Accepted)

let main () =
  let n,a,b = Scanf.scanf "%d %d %d\n" (fun a b c -> a, b, c) in
  let rec func acc n = if n = 0 then acc else func (acc + (n mod 10)) (n / 10) in
  let res = ref 0 in
  for i = 1 to n do
    let s = func 0 i in
    if a <= s && s <= b then res := !res + i;
  done;
  Printf.printf "%d\n" !res

let _ = main ()