#[allow(unused_macros)]
macro_rules! debug {
    ($($a:expr),*) => {
        #[cfg(debug_assertions)]
        writeln!(&mut std::io::stderr(), concat!("[DEBUG] ", $(stringify!($a), "={:?} "),*), $($a),*);
    }
}

#[allow(unused_imports)]
use std::cmp::{min, max};
#[allow(unused_imports)]
use std::io::{stdout, stdin, BufWriter, Write};

#[derive(Debug)]
pub struct UnionFind {
    par: Vec<usize>,
}
impl UnionFind {
    pub fn new(n: usize) -> UnionFind {
        let mut vec = vec![0; n];
        for i in 0..n {
            vec[i] = i;
        }
        UnionFind { par: vec }
    }
    pub fn find(&mut self, x: usize) -> usize {
        if x == self.par[x] {
            x
        } else {
            let par = self.par[x];
            let res = self.find(par);
            self.par[x] = res;
            res
        }
    }
    pub fn same(&mut self, a: usize, b: usize) -> bool {
        self.find(a) == self.find(b)
    }
    pub fn unite(&mut self, a: usize, b: usize) {
        let apar = self.find(a);
        let bpar = self.find(b);
        self.par[apar] = bpar;
    }
}

fn main() {
    let out = std::io::stdout();
    let mut out = BufWriter::new(out.lock());
    macro_rules! puts {
        ($($format:tt)*) => (write!(out,$($format)*).unwrap());
    }

    let stdin = std::io::stdin();
    let mut sc = Scanner { reader: stdin.lock() };

    let h:usize = sc.read();
    let w:usize = sc.read();

    let mut f = vec![];
    for _ in 0..h {
        let r:Vec<usize> = sc.read_vec(w);
        f.push(r);
    }

    use std::collections::VecDeque;
    let mut uf = UnionFind::new(h*w);
    for x in 0..h {
        for y in 0..w {
            if f[x][y] == 0 {
                continue;
            }
            let x = x as i64;
            let y = y as i64;
            let ds = vec![
                (x+1, y),
                (x, y+1),
                (x-1, y),
                (x, y-1),
            ];
            for (nx, ny) in ds {
                if nx < 0 || ny < 0 {
                    continue;
                }
                let x = x as usize;
                let y = y as usize;
                let nx = nx as usize;
                let ny = ny as usize;

                if nx >= h || ny >= w {
                    continue;
                }
                if f[nx][ny] == 0 {
                    continue;
                }
                uf.unite(x*w+y, nx*w+ny);
            }
        }
    }

    let mut ans = vec![];
    for x in 0..h {
        for y in 0..w {
            if f[x][y] == 1 {
                ans.push(uf.find(x*w+y));
            }
        }
    }
    ans.sort();
    ans.dedup();
    puts!("{}\n", ans.len());
}

pub struct Scanner<R> {
    reader: R,
}
impl<R: std::io::Read> Scanner<R> {
    pub fn read<T: std::str::FromStr>(&mut self) -> T {
        use std::io::Read;
        let buf: String = self
            .reader
            .by_ref()
            .bytes()
            .map(|b| b.unwrap() as char)
            .skip_while(|c| c.is_whitespace())
            .take_while(|c| !c.is_whitespace())
            .collect();
        buf.parse::<T>().ok().expect("Parse error.")
    }
    pub fn read_vec<T: std::str::FromStr>(&mut self, n: usize) -> Vec<T> {
        (0..n).map(|_| self.read()).collect()
    }
    pub fn chars(&mut self) -> Vec<char> {
        self.read::<String>().chars().collect()
    }
}