#include<iostream>
#include<vector>
#include<stack>

int main() {
    int H, W;
    std::cin >> H >> W;
    std::vector<std::vector<bool>> A(H, std::vector<bool>(W));
    for (int h = 0; h < H; ++h) {
        for (int w = 0; w < W; ++w) {
            int a;
            std::cin >> a;
            A.at(h).at(w) = bool(a);
        }
    }

    const std::vector<std::pair<int, int>> dhw = {{0,  1},
                                                  {1,  0},
                                                  {0,  -1},
                                                  {-1, 0}};

    std::vector<std::vector<bool>> nonvisited(H, std::vector<bool>(W, true));
    int ans = 0;

    for (int h0 = 0; h0 < H; ++h0) {
        for (int w0 = 0; w0 < W; ++w0) {
            if (A.at(h0).at(w0) && nonvisited.at(h0).at(w0)) {
                ans++;
                std::stack<std::pair<int, int>> stk;
                stk.emplace(h0, w0);
                while (!stk.empty()) {
                    const auto [h, w] = stk.top();
                    stk.pop();
                    for (const auto &[dh, dw]: dhw) {
                        const int hdh = h + dh;
                        const int wdw = w + dw;
                        if (0 <= hdh
                            && hdh < H
                            && 0 <= wdw
                            && wdw < W
                            && A.at(hdh).at(wdw)
                            && nonvisited.at(hdh).at(wdw)) {
                            stk.emplace(hdh, wdw);
                        }
                    }
                }
            }
        }
    }
    std::cout << ans << std::endl;
}