Rook

Given a chessboard of size $n\times m$, i.e., with $n$ rows and $m$ columns.

There is only one piece on this chessboard — a rook. It is located in the bottom left corner. There are no other pieces.

Recall that a rook can move any number of cells horizontally or vertically in one move, but not diagonally.

Find the number of cells the rook can move to in one move.

The image shows a traditional chessboard of size $8\times 8$. On this board, the rook can move to all the cells marked in green. There are a total of $14$ such cells, so the answer is $14$.

Input

The first line contains a single integer $n$ ($1\le n\le 20$).

The second line contains a single integer $m$ ($1\le m\le 20$).

Output

Output the number of cells the rook can move to in one move.

Examples

Note

An explanation of why the answer to the first example is $14$ can be seen in the image above.

In the second example, the answer is $3$, because the rook can only move one position up and two positions to the right.