#include <bits/stdc++.h>
using namespace std;

using int64 = long long;
using uint64 = unsigned long long;

int dr[4] = {1, 0, -1, 0},
    dc[4] = {0, 1, 0, -1};

const int MAX_H = 3000;
const int MAX_W = 3000;

int H, W, A[MAX_H][MAX_W];
bool isVisited[MAX_H][MAX_W];

bool isInside(int r, int c)
{
    return 0 <= r and r < H and 0 <= c and c < W;
}

void bfs(int r, int c)
{
    queue<pair<int, int>> Q;
    isVisited[r][c] = true;
    Q.push(make_pair(r, c));

    while (!Q.empty())
    {
        auto pos = Q.front(); Q.pop();

        for (int i = 0; i < 4; i++)
        {
            int nr = pos.first + dr[i],
                nc = pos.second + dc[i];
            if (isInside(nr, nc) and !isVisited[nr][nc] and A[nr][nc] == 1)
            {
                isVisited[nr][nc] = true;
                Q.push(make_pair(nr, nc));
            }
        }
    }
}

int counting()
{
    int cnt = 0;

    for (int r = 0; r < H; r++)
    {
        for (int c = 0; c < W; c++)
        {
            if (!isVisited[r][c] and A[r][c] == 1)
            {
                cnt++;
                bfs(r, c);
            }
        }
    }

    return cnt;
}

int main()
{
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    cin >> H >> W;

    for (int r = 0; r < H; r++)
    {
        for (int c = 0; c < W; c++)
        {
            cin >> A[r][c];
        }
    }

    cout << counting() << endl;

    return 0;
}