import java.math.BigInteger;

public class prob216 {
	public static void main(String args[])
	{
		BigInteger n,mult,i,max,subt;
		i = new BigInteger("2");
		mult = new BigInteger("2");
        //max = new BigInteger("10000");
		max = new BigInteger("50000000");
        int x = 0;
		while (i.compareTo(max) <= 0) {
			n = i.pow(2).multiply(mult).subtract(BigInteger.ONE);
			if (n.isProbablePrime(3)) {
                x++;
                if (x % 10000 == 0)
                    System.out.println("Total: (" + i + ") " + x);
            }
            i = i.add(BigInteger.ONE);
        }
        
        System.out.println("Total: " + x);
    }
}