#include <iostream>
using namespace std;

int main(int argc, char** argv) {

int primeFactorCheck = 0;


for (int factorCheck = 2; factorCheck < 600851475143; ++factorCheck)
{
    //primeFactorCheck = factorCheck - 1;


    for (int primeFactorCheck = factorCheck - 1; factorCheck % primeFactorCheck != 0 and 600851475143 % factorCheck == 0 and primeFactorCheck > 1; --primeFactorCheck)
   	{

		if (primeFactorCheck == 2)
		{
			cout << factorCheck << " is a prime factor within 600851475143!" << endl;
			break;
		}



	}


}

}