using System;
using System.Collections.Generic;
using System.Linq;
using static System.Console;

class Program
{
    static void Main()
    {
        var HW = ReadLine().Split().Select(int.Parse).ToArray();
        var H = HW[0];
        var W = HW[1];
        var map = new int[H, W];
        var zero = 0;
        for (int i = 0; i < H; i++)
        {
            var line = ReadLine().Split().Select(int.Parse).ToArray();
            for (int j = 0; j < W; j++)
            {
                map[i, j] = line[j];
                if (line[j] == 0) zero++;
            }
        }

        var uf = new UnionFind(H * W);
        for (int i = 0; i < H; i++)
        {
            for (int j = 0; j < W; j++)
            {
                if (map[i, j] == 0) continue;
                var m = i * W + j;
                if (j != W - 1 && map[i, j + 1] == 1) uf.Unite(m, m + 1);
                if (i != H - 1 && map[i + 1, j] == 1) uf.Unite(m, m + W);
            }
        }
        WriteLine(uf.count - zero);
    }
}

class UnionFind
{
    public int count;
    int[] parent;
    int[] rank;

    public UnionFind(int size)
    {
        var b = new int[size];
        for (int i = 0; i < b.Length; i++)
        {
            b[i] = i;
        }
        parent = b;
        rank = new int[size];
        count = size;
    }

    int Root(int x) => parent[x] == x ? x : parent[x] = Root(parent[x]);

    public bool Same(int x, int y) => Root(x) == Root(y);

    public void Unite(int x, int y)
    {
        x = Root(x);
        y = Root(y);
        if (x == y) return;
        count--;
        if (rank[x] < rank[y])
        {
            parent[x] = y;
        }
        else
        {
            parent[y] = x;
            if (rank[x] == rank[y]) rank[x]++;
        }
    }
}