//4  Eikasia tou Goldbach
//Ka8e artios akeraios n>2 mporei na ekfrastei 
//san to auroisma dyo prwtwn, n=p+q
#include <iostream>
using namespace std;

bool isPrime(int n);

int main()
{   int n, i;
    bool flag = false;
    do { 
    cout << "Dose ena artio akeraio > 2: ";
    cin >> n;
    } while (n<=2 || n%2==1);
    for(i = 2; i <= n/2; i++)
    {   if (isPrime(i))
        {   if (isPrime(n - i))
            {  cout << n << " = " << i << " + " << n-i << endl;
               flag = true;
            }
        }
    }
    if (!flag) cout << n << " den ekfrazetai san athroisma 2 prwtwn.";
    system("PAUSE"); 
    return 0;
}

// Elegxos gia prwto
bool isPrime(int n)
{   int i;
    bool ip = true;
    for(i = 2; i <= n/2; i++)
    {   if (n % i == 0)
        {  ip = false;
           break;
        }
    }
    return ip;
}