#include <iostream>
#include <vector>
#include <queue>

template <class T>
std::vector<T> vec(int len, T elem) { return std::vector<T>(len, elem); }

const std::vector<int> dx{-1, 0, 1, 0}, dy{0, -1, 0, 1};

void solve() {
    int h, w;
    std::cin >> h >> w;

    auto grid = vec(h, vec(w, 0));
    for (auto& v : grid) {
        for (auto& x : v) {
            std::cin >> x;
        }
    }

    int ans = 0;
    for (int sx = 0; sx < h; ++sx) {
        for (int sy = 0; sy < w; ++sy) {
            if (grid[sx][sy] == 0) continue;

            ++ans;

            grid[sx][sy] = 0;
            std::queue<std::pair<int, int>> que;
            que.emplace(sx, sy);

            while (!que.empty()) {
                auto [x, y] = que.front();
                que.pop();

                for (int i = 0; i < 4; ++i) {
                    int nx = x + dx[i],
                        ny = y + dy[i];

                    if (nx < 0 || h <= nx ||
                        ny < 0 || w <= ny ||
                        grid[nx][ny] == 0) continue;

                    grid[nx][ny] = 0;
                    que.emplace(nx, ny);
                }
            }
        }
    }

    std::cout << ans << "\n";
}

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

    solve();

    return 0;
}