import std.experimental.all;

T read(T)() { return readln.chomp.to!T; }
T[] reads(T)() { return readln.split.to!(T[]); }
alias readint = read!int;
alias readints = reads!int;

int calc(int[][] g) {
    int rows = cast(int)g.length;
    int cols = cast(int)g[0].length;

    auto delta = [[-1, 0], [1, 0], [0, -1], [0, 1]];

    void fill(int row, int col, int[][] g, bool[][] used) {
        assert(g[row][col] == 1);

        auto q = DList!(int)();
        // [row, col] で配列生成すると TLE (2 sec 近く遅くなる)
        q.insertBack((row << 16) | col);
        while (!q.empty) {
            auto a = q.front;
            q.removeFront();

            int r = (a >> 16), c = a & 0xffff;
            if (used[r][c]) continue;
            used[r][c] = true;

            foreach (d; delta) {
                int r2 = r + d[0];
                int c2 = c + d[1];
                if (!(0 <= r2 && r2 < rows && 0 <= c2 && c2 < cols)) continue;
                if (g[r2][c2] == 0 || used[r2][c2]) continue;

                q.insertBack((r2 << 16) | c2);
            }
        }
    }

    int ans = 0;
    auto used = new bool[][](rows, cols);
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            if (used[i][j]) continue;
            if (g[i][j] == 1) {
                ans++;
                fill(i, j, g, used);
            }
        }
    }
    return ans;
}

void main() {
    auto hw = readints;
    int h = hw[0], w = hw[1];
    auto g = new int[][](h, w);
    for (int i = 0; i < h; i++) {
        g[i][] = readints;
    }

    writeln(calc(g));
}