//Java import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int x = sc.nextInt(); int y = sc.nextInt(); if (x == y || x == y + 2) { if (x % 2 == 0) { System.out.println(x + y); } else { System.out.println(x + y - 1); } } else { System.out.println("No Number"); } } } #Python x, y = map(int, input().split()) if x == y or x == y + 2: if x % 2 == 0: print(x + y) else: print(x + y - 1) else: print('No Number')