#![allow(non_snake_case)]

#[allow(unused_macros)]
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut tokens = $s.split_whitespace();
        input_inner! { tokens, $($r)* }
    };

    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut res = String::new();
            ::std::io::stdin().read_to_string(&mut res).unwrap();
            res
        };
        let mut tokens = s.split_whitespace();
        input_inner! { tokens, $($r)* }
    };
}

#[allow(unused_macros)]
macro_rules! input_inner {
    ($tokens:expr)  => {};
    ($tokens:expr,) => {};

    ($tokens:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($tokens, $t);
        input_inner! { $tokens $($r)* }
    };
}

#[allow(unused_macros)]
macro_rules! read_value {
    ($tokens:expr, ( $($t:tt),* )) => {
        ( $(read_value!($tokens, $t)),* )
    };

    ($tokens:expr, [ $t:tt; $len:expr ]) => {
        (0..$len).map(|_| read_value!($tokens, $t)).collect::<Vec<_>>()
    };

    ($tokens:expr, chars) => {
        read_value!($tokens, String).chars().collect::<Vec<_>>()
    };

    ($tokens:expr, usize1) => {
        read_value!($tokens, usize) - 1
    };

    ($tokens:expr, $t:ty) => {
        $tokens.next().unwrap().parse::<$t>().expect("parse error")
    };
}

struct UnionFind {
    v: Vec<usize>,
}

impl UnionFind {
    fn new(size: usize) -> Self {
        let mut v = vec![0usize; size];
        for i in 0..size {
            v[i] = i;
        }
        Self {
            v,
        }
    }

    fn root(&mut self, x: usize) -> usize {
        let parent = self.v[x];
        if parent == x { return x; }
        let res = self.root(parent);
        self.v[x] = res;
        res
    }

    fn unite(&mut self, x: usize, y: usize) {
        let rootx = self.root(x);
        let rooty = self.root(y);
        self.v[rooty] = rootx;
    }
}

fn main() {
    input! {
        H: usize,
        W: usize,
        //M: [[u8; W]; H],
        M: [u8; W*H],
    }

    let mut uf = UnionFind::new(H*W);
    for y in 0..H { for x in 0..W {
        let idx = W*y + x;
        if x < W-1 && M[idx] == M[idx+1] {
            uf.unite(idx, idx+1);
        }
        if y < H-1 && M[idx] == M[idx+W] {
            uf.unite(idx, idx+W);
        }
    }}

    let mut ans = 0;
    for i in 0..H*W {
        if i == uf.v[i] && M[i] == 1 {
            ans += 1;
        }
    }
    println!("{}", ans);
}