Bounce

import java.util.Arrays;
import java.util.Scanner;

public class Bounce {

    private static String[] directions = {"DR", "DL", "UR", "UL"};
    private static String direction = directions[0];
    private static Scanner scanner = new Scanner(System.in);
    private static long[][] matrix;
    private static int row = -1;
    private static int col = -1;
    private static long sum = 0;

    public static void main(String[] args) {

        int r = scanner.nextInt();
        int c = scanner.nextInt();

        matrix = new long[r][c];

        if (r == 1 || c == 1){
            sum = 1;
            Exit();
        }

        initMatrix();

        while (true) {

            proceed();

        }

    }

    private static void proceed() {

        boolean success = true;

        switch (direction) {
            case "DR":
                success = moveDownRight();
                break;
            case "DL":
                success = moveDownLeft();
                break;
            case "UL":
                success = moveUpLeft();
                break;
            case "UR":
                success = moveUpRight();
                break;
        }
        if (success){
            sum += matrix[row][col];
        }
    }

    private static boolean moveDownRight() {
        if (invalidDown() && invalidRight()) {
            Exit();
        } else if (invalidDown()) {
            direction = directions[2];
            return false;
        } else if (invalidRight()) {
            direction = directions[1];
            return false;
        }
        row++;
        col++;
        direction = directions[0];
        return true;
    }

    private static boolean moveDownLeft() {
        if (invalidDown() && invalidLeft()) {
            Exit();
        } else if (invalidDown()) {
            direction = directions[3];
            return false;
        } else if (invalidLeft()) {
            direction = directions[0];
            return false;
        }
        row++;
        col--;
        direction = directions[1];
        return true;
    }

    private static boolean moveUpRight() {
        if (invalidUp() && invalidRight()) {
            Exit();
        } else if (invalidUp()) {
            direction = directions[0];
            return false;
        } else if (invalidRight()) {
            direction = directions[3];
            return false;
        }
        row--;
        col++;
        direction = directions[2];
        return true;
    }

    private static boolean moveUpLeft() {
        if (invalidUp() && invalidLeft()) {
            Exit();
        } else if (invalidUp()) {
            direction = directions[1];
            return false;
        } else if (invalidLeft()) {
            direction = directions[2];
            return false;
        }
        row--;
        col--;
        direction = directions[3];
        return true;
    }

    private static boolean invalidDown() {
        return row + 1 >= matrix.length;
    }

    private static boolean invalidUp() {
        return row - 1 < 0;
    }

    private static boolean invalidRight() {
        return col + 1 >= matrix[0].length;
    }

    private static boolean invalidLeft() {
        return col - 1 < 0;
    }

    private static void Exit(){
        System.out.println(sum);
        System.exit(0);
    }

    private static void initMatrix() {

        int firstInRow = 1;
        for (int r = 0; r < matrix.length; r++) {

            matrix[r][0] = firstInRow;
            firstInRow *= 2;

            for (int c = 1; c < matrix[r].length; c++) {
                matrix[r][c] = 2 * matrix[r][c - 1];
            }
        }
    }

    private static void printMatrix() {

        for (int i = 0; i < matrix.length; i++) {
            System.out.println(Arrays.toString(matrix[i]));
        }
    }
}