Fields P45829

A rectangular field of size $m\times n$ contains $mn$ square areas. Some of the areas are occupied by a determinated growing (tomatoes, carrots, etc.) that is identified by a natural number strictly positive. It is known that growings are grouped in different disjointed rectangles and that a growing always is separated of another one by areas without grownings, identify by the value 0.

Write a program that reads fields and prints the number of rectangular growings.

Input

Input consists in a sequence of fields. For each field, it is given two natural numbers $m$ and $n$ with $m\ge1$ and $n\ge1$ that represent the size of the field. Then, it is given $m$ rows, each one with $n$ natural numbers that represent the growing of the area. The fields follow the hypotheses described previously.

Output

For each fielf of the input, print in a line the number of rectangular growings.