практикум 4 VII. 13

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace практикум_4.VII._13
{
    class Program
    {
        static int NextLowerNumber(int c, int d, int n)
        {
            int k;
            int number;
            int tmp = -1;
            bool flag = true;
            for (int i = n-1; i > 0 && flag; i--)
            {
                k = 0;
                number = i;
                while (number > 0)
                {
                    k += number % 10;
                    number /= 10;
                }
                if ((k % c == 0) || (k % d == 0))
                {
                    flag = false;
                    tmp = i;
                }

            }
            return tmp;
        }
        static void Main(string[] args)
        {
            Console.WriteLine("Enter c:");
            int c = int.Parse(Console.ReadLine());
            Console.WriteLine("Enter d:");
            int d = int.Parse(Console.ReadLine());
            Console.WriteLine("Enter N:");
            int n = int.Parse(Console.ReadLine());
            int res = NextLowerNumber(c, d, n);
            if (res == -1)
                Console.WriteLine("none minimal number is not divisible by c and d");
            else Console.WriteLine("{0}", res);
        }
    }
}