#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 reached[3000][3001];
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};

void dfs(int y, int x)
{
    a[y][x] = 0;
    reached[y][x] = 1;
    for (int i = 0; i < 4; i++)
    {
        int nx = x + dx[i];
        int ny = y + dy[i];
        if (0 <= nx && nx < w && 0 <= ny && ny < h && a[ny][nx] == 1 && !(reached[ny][nx]))
            dfs(ny, nx);
    }
    return;
}

void solve()
{
    int ans = 0;
    for (int i = 0; i < h; i++)
    {
        for (int j = 0; j < w; j++)
        {
            if (a[i][j] == 1)
            {
                dfs(i, j);
                ans++;
            }
        }
    }
    printf("%d\n", ans);
}

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