using System;

public class Program

{

    public static void Main()

    {

        // https://projecteuler.net/problem=7

        // What is the 10,001 st prime number?

        var nthNumber = 1;

        var prime =  getNthPrimeNumber(nthNumber);      

        Console.WriteLine("The {0} primenumber is {1}.", nthNumber, prime);

    }

    private static int getNthPrimeNumber(int nthNumber)

    {

        if(nthNumber <= 0){

            throw new Exception("Stefano is a cotton headed ninny muggin");

        }

        var primesFound = 0;

        var lastPrimeFound = 1;     

        while(true)

        {

            if(primesFound.Equals(nthNumber))

                break;                                  

            lastPrimeFound++;

            if(isPrime(lastPrimeFound))             

                primesFound++;

        }       

        return lastPrimeFound;      

    }

    private static bool isPrime(int number) 

    {       

        if (number <= 1)

            return false;

​

        if (number == 2 || number == 3)

            return true;  

​

        if (number % 2 == 0 || number % 3 == 0 || (number % 5 == 0 && number != 5))

            return false;

        // checking from 3 up 

        for(var i = 3; i <= Math.Sqrt(number); i+=2)

            if (number % i == 0) return false;          

​

            return true;

    }   

}