You are given a rectangular board of *M* × *N* squares. Also you are given an unlimited number of standard domino pieces of 2 × 1 squares. You are allowed to rotate the pieces. You are asked to place as many dominoes as possible on the board so as to meet the following conditions:

1. Each domino completely covers two squares.

2. No two dominoes overlap.

3. Each domino lies entirely inside the board. It is allowed to touch the edges of the board.

Find the maximum number of dominoes, which can be placed under these restrictions.
In a single line you are given two integers *M* and *N* — board sizes in squares (1 ≤ *M* ≤ *N* ≤ 16).
#Sabiendo que el split nos crea un listado con las variables 
M,N=map(int,input().split())#Se asigna los outputs a un map de iteración de dos variables donde se especifica el tamaño del rectangulo,

if M==1 and N==1: #Cuando el rectangulo es de 1X1 no es posible que el domino quepa en este
    print("No es posible") 

else: #Al no ser de 1X1 pasa a un proceso de else y se cubre el número de casillas con el tamaño de domino que es dos 
    print(int(M*N) // 2) #Se imprime el resultado de cuantos dominos pueden caber en el rectangulo 