import java.util.*;
import java.io.*;

public class Main {
    
    private static int[] dy = {0,1,0,-1};
    private static int[] dx = {1,0,-1,0};
    private static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    
    public static void main(String[] args) throws Exception {

        try {

    		int[] h_w = readIntArray();
            int h = h_w[0];
            int w = h_w[1];
            
            int[][] field = new int[h][w];
            for(int i = 0 ; i < h ; i++){
                
                int[] terrains = readIntArray();
                field[i] = terrains;
                
            }
            
            ArrayDeque<Pair> todo = new ArrayDeque<>();
            int ans = 0;
            for(int i = 0 ; i < h ; i++){
                for(int j = 0 ; j < w ; j++){
                    
                    int currentH = i;
                    int currentW = j;
                    if(field[currentH][currentW] == 0){
                        continue;
                    }
                    
                    Pair p = new Pair(currentH , currentW);
                    field = bfs(field , p , h , w , todo);
                    ans++;
                    
                }
            }
            
            System.out.println(ans);

		} catch (Exception e) {

            System.out.println("エラー");
       
		}
		
    }
    
    private static int[][] bfs(int[][] field , Pair p , int h , int w , ArrayDeque<Pair> todo){
     
        todo.clear();
        todo.add(p);
        
        while(!todo.isEmpty()){
            
            Pair pair = todo.remove();
            int currentH = pair.getY();
            int currentW = pair.getX();
            
            field[currentH][currentW] = 0;
            
            for(int i = 0 ; i < 4 ; i++){
                
                int nextH = currentH + dy[i];
                int nextW = currentW + dx[i];
                
                if (nextH < 0 || nextW < 0 || nextH >= h || nextW >= w) {
					continue;
                }
                if(field[nextH][nextW] == 0){
                    continue;
                }
                
                Pair np = new Pair(nextH , nextW);
                todo.add(np);
                
            }

        }
        
        return field;
                
    }
    
    private static int[] readIntArray() throws Exception{
        
		int[] intArray = Arrays.stream(br.readLine().split(" "))
							.mapToInt(Integer::parseInt).toArray();

		return intArray;

	}

}

class Pair{
    
    int y , x;
    
    public Pair(int y  , int x){
        this.y = y;
        this.x = x;
    }
    
    public int getY(){
        return y;
    }
    
    public int getX(){
        return x;
    }
    
}