import std;

void main() {
    int H, W;
    readf("%d %d\n", H, W);

    auto A = new int[][](H, W);
    foreach (i; 0 .. H) {
        A[i] = readln.chomp.split.to!(int[]);
    }

    auto deltaX = [-1, 0, 1, 0], deltaY = [0, 1, 0, -1];

    int[] que;

    int res;

    foreach (i; 0 .. H) {
        foreach (j; 0 .. W) {
            if (A[i][j] == 0) {
                continue;
            }

            ++res;

            que ~= i * W + j;

            while (!que.empty) {
                auto f = que.front;
                que.popFront;

                int x = f / W;
                int y = f % W;

                A[x][y] = 0;

                foreach (dx, dy; zip(deltaX, deltaY)) {
                    auto nx = x, ny = y;
                    nx += dx, ny += dy;

                    if (nx < 0 || nx >= H || ny < 0 || ny >= W) {
                        continue;
                    }

                    if (A[nx][ny] == 0) {
                        continue;
                    }

                    que ~= nx * W + ny;
                }
            }
        }
    }

    res.writeln;
}