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 C# (.NET Core 3.1.201) (judge verdict: Accepted)

using System;
using System.Linq;

namespace ProgramingStydying
{
    class Program
    {
        static void Main(string[] args)
        {
            var input = Console.ReadLine().Split().Select(int.Parse).ToArray();
            var n = input[0];
            var a = input[1];
            var b = input[2];

            var ans = 0;

            for(int M = 1; M <= n; M++)
            {
                var m = M;
                var sum = 0;
                while(m > 0)
                {
                    sum += m % 10;
                    m /= 10;
                }
                if (sum >= a && sum <= b)
                {
                    ans += M;
                }
            }
            Console.WriteLine(ans);
        }
    }
}