use std::io;

fn main() {
    let mut input = String::new();
    io::stdin().read_line(&mut input).unwrap();
    let mut values = input.trim().split_whitespace().map(|s| s.parse::<i32>().unwrap());
    let h = values.next().unwrap();
    let w = values.next().unwrap();

    let mut a = Vec::new();
    for _ in 0..h {
        input.clear();
        io::stdin().read_line(&mut input).unwrap();
        a.extend(input.trim().split_whitespace().map(|s| s.parse::<i32>().unwrap()));
    }

    let mut ans = 0;
    let mut use_grid = vec![0; (h * w) as usize];

    for i in 0..h {
        for j in 0..w {
            let index = (i * w + j) as usize;
            if a[index] == 1 && use_grid[index] == 0 {
                ans += 1;
                let mut q = vec![(i, j)];
                use_grid[index] = 1;

                while !q.is_empty() {
                    let (x, y) = q.pop().unwrap();
                    for (dx, dy) in &[(1, 0), (-1, 0), (0, 1), (0, -1)] {
                        let u = x + dx;
                        let v = y + dy;
                        if u >= 0 && u < h && v >= 0 && v < w && a[(u * w + v) as usize] == 1 && use_grid[(u * w + v) as usize] == 0 {
                            use_grid[(u * w + v) as usize] = 1;
                            q.push((u, v));
                        }
                    }
                }
            }
        }
    }

    println!("{}", ans);
}