Read Picture And Print Out Number Of Blocks - Counting In Multidimensional Array

I have to write a program that will read a picture and then print out the number of blocks inside it.

I have to read the picture as a binary matrix of the size r - c (number of rows times number of columns). The blocks are groups of one or more adjacent elements with the value 1.

- Blocks are built exclusively of elements with value 1
- Each element with value 1 is a part of some block
- Adjacent elements with value 1 belong to the same molecule.

We only take into account the horizontal and vertical adjacency but not diagonal.

INPUT:

In the first line of the input we have the integers r and c, separated with one space.
Then we have the r lines, where each contains s 0's and 1's.
The numbers inside the individual lines are NOT separated by spaces.

The OUTPUT only print the number of blocks in the picture.

Example:

INPUT:
7 5
01000
00010
00000
10000
01000
00001
00100

OUTPUT:
6

THIS IS WHAT I CAME UP SO FAR:

import java.util.Scanner;
class Blocks{
public static void main(String[] args){
Scanner sc=new Scanner(System.in);
char ch[][];
int rowNum=sc.nextInt();
int columnNum=sc.nextInt();

[Code] ....