NumOfCoprime.cs

class Program
    {
        static void Main(string[] args)
        {
            int numOfCoPrimes = 0;
            for (int i = 1; i < 1225; i++)
            {
                int g = gdc(i, 1225);
                if (g == 1)
                    numOfCoPrimes++;
            }

            Console.WriteLine(numOfCoPrimes);
        }
        
        static int gdc(int a, int b)
        {
            int gdc = 1;
            for (int i = 2; i <= Math.Min(a, b); i++)
            {
                if (a % i == 0 && b % i == 0)
                {
                    gdc = i;
                }
            }

            return gdc;
        }
        
    }