using System;

using System.Globalization;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine(Rotate(30, 10));

    }

​

    private static int Rotate(int n, int m)

    {

        if (n <= m)

            return n;

        var auxM = 0;

        for (var i = 1; i <= n; i++)

        {

            if (auxM == m)

                auxM = 0;

            else

                auxM++;

        }

​

        return auxM;

    }

}