import java.util.Scanner;

public class alternatechecker {
	public static void main(String[] args) {

			Scanner in = new Scanner(System.in);
					int[] num = new int[10];
					int sum = 0;
					int sign = 1;

				for (int i = 0; i < 10; i++)
				{
					System.out.println("Numbers please" + (i+1) );
					num [i] = in.nextInt();
					sum += sign*num[i];
					sign *= -1;
				}

				System.out.println("sum = " + sum);
	}

}