import java.util.Scanner;
public class Lab03_Task01C {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        String line = s.nextLine();
        String[] numbers = line.split("\\s+");
        int x = Integer.parseInt(numbers[0]), y = Integer.parseInt(numbers[1]), z = Integer.parseInt(numbers[2]);
        x = x-1;
        z = z+2;
        int total = ((x+y)+(y-z)+(x*z))/3;
        System.out.println("Result of Magic calculations = "+total);
    }
}