# 原始题目

## A - Garden

• Time limit : 2sec / Memory limit : 1000MB
• Score: 100 points

### Problem Statement

There is a farm whose length and width are A yard and B yard, respectively. A farmer, John, made a vertical road and a horizontal road inside the farm from one border to another, as shown below: (The gray part represents the roads.)

What is the area of this yard excluding the roads? Find it.

### Note

It can be proved that the positions of the roads do not affect the area.

### Constraints

• A is an integer between 2 and 100 (inclusive).
• B is an integer between 2 and 100 (inclusive).

### Input

Input is given from Standard Input in the following format:

A B


### Output

Print the area of this yard excluding the roads (in square yards).

### Sample Input 1

2 2


### Sample Output 1

1


In this case, the area is 1 square yard.

### Sample Input 2

5 7


### Sample Output 2

24


In this case, the area is 24 square yards.