#include <bits/stdc++.h>

using namespace std;

using ll = long long;

const int dh[] = {1, -1, 0, 0};
const int dw[] = {0, 0, 1, -1};

bool f[3005][3005];

void dfs(int ch, int cw) {
    f[ch][cw] = false;
    for (int i = 0; i < 4; i++) {
        int nh = ch + dh[i], nw = cw + dw[i];
        if (!f[nh][nw]) continue;
        f[nh][nw] = false;
        dfs(nh, nw);
    }
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int H, W;
    cin >> H >> W;
    for (int i = 1; i <= H; i++) {
        for (int j = 1; j <= W; j++) {
            cin >> f[i][j];
        }
    }

    int ans = 0;
    for (int i = 1; i <= H; i++) {
        for (int j = 1; j <= W; j++) {
            if (f[i][j]) {
                dfs(i, j);
                ans++;
            }
        }
    }
    cout << ans << endl;
    return 0;
}