Given a $2$d grid map of $\text{'}1\text{'}$s $($wood$)$ and $\text{'}0\text{'}$s $($water$),$ count the boats in the sea.

A boat is surrounded by water and is formed by connecting adjacent wood horizontally or vertically. You may assume all four edges of the grid are all surrounded by water.

A single wood surrounded by water is also considered as a boat. Find the number of boats in the sea.

Let $R$ be the number of rows and $C$ be the number of columns in the grid.

Input format:

The first line consists of $2$ integers R and C$.$

Followed by a matrix of size R x C$.$

Output format:

Print the number of boats in a sea.

Constraints

$0R100$

$0C100$

Examples

Input:

$44$

$1011$

$0000$

$1100$

$1101$

Output:

$4$