using System;

public class Program

{

    public static void Main()

    {

        //A prime number is a positive integer that is divisible only by 1 and itself. For example: 2, 3, 5, 7, 11, 13, 17

        //Print prime numbers from 1 to 20.

        for(int i=2; i <= 100; i++)

        {

            int primeNo = i;

            for(int j=2; j <=i/2; j++)

            {               

                if( i!=j && i%j == 0)

                {                   

                    primeNo = 0;

                    break;

                }

            }

            if(primeNo != 1 && primeNo > 0)

            {

                Console.WriteLine($"{i} is a prime number");

            }

        }

    }

}