#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <string>
#include <sstream>
#include <complex>
#include <vector>
#include <list>
#include <queue>
#include <deque>
#include <stack>
#include <map>
#include <set>
using namespace std;
typedef long long unsigned int ll;

#define EPS (1e-7)
#define INF (1e9)
#define PI (acos(-1))

//入力
int h, w;
int a[3000][3001];
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};

int bfs()
{
    int ans = 0;
    for (int sy = 0; sy < h; sy++)
    {
        for (int sx = 0; sx < w; sx++)
        {
            if (a[sy][sx] == 1)
            {
                ans++;
                queue<pair<int, int>> que;
                que.push({sy, sx});
                while (que.size())
                {
                    pair<int, int> p = que.front();
                    que.pop();
                    for (int i = 0; i < 4; i++)
                    {
                        int ny = p.first + dy[i];
                        int nx = p.second + dx[i];
                        if (0 <= nx && nx < w && 0 <= ny && ny < h && a[ny][nx] == 1)
                        {
                            que.push({ny, nx});
                            a[ny][nx] = 0;
                        }
                    }
                }
            }
        }
    }
    return ans;
}

void solve()
{
    printf("%d\n", bfs());
}

int main()
{
    cin >> h >> w;
    for (int i = 0; i < h; i++)
    {
        for (int j = 0; j < w; j++)
        {
            cin >> a[i][j];
        }
    }
    solve();
}