Contest Duration: - (local time) (100 minutes) Back to Home
A - Garden /

Time Limit: 2 sec / Memory Limit: 976 MB

﻿配点: 100

### 問題文

A ヤード、横 B ヤードの畑がある. 農夫ジョンは, 畑の内部に, 畑の上端と下端を結ぶ縦方向の幅 1 ヤードの道, 畑の左端と畑の右端を結ぶ横方向の幅 1 ヤードの道を作った. 畑は下図のようになっている. (灰色の部分が道)

さて, 道を除いた畑の面積は, 何平方ヤードだろうか? 求めなさい.

### 制約

• A2 以上 100 以下の整数
• B2 以上 100 以下の整数

### 入力

A B


### 入力例 1

2 2


### 出力例 1

1


この場合, 面積は 1 平方ヤードになる.

### 入力例 2

5 7


### 出力例 2

24


この場合, 面積は 24 平方ヤードになる.

﻿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.