#include <bits/stdc++.h>
using namespace std;

typedef long long   signed int LL;
typedef long long unsigned int LU;

#define incID(i, l, r) for(int i = (l)    ; i <  (r); i++)
#define incII(i, l, r) for(int i = (l)    ; i <= (r); i++)
#define decID(i, l, r) for(int i = (r) - 1; i >= (l); i--)
#define decII(i, l, r) for(int i = (r)    ; i >= (l); i--)
#define  inc(i, n) incID(i, 0, n)
#define inc1(i, n) incII(i, 1, n)
#define  dec(i, n) decID(i, 0, n)
#define dec1(i, n) decII(i, 1, n)

#define inII(v, l, r) ((l) <= (v) && (v) <= (r))
#define inID(v, l, r) ((l) <= (v) && (v) <  (r))

#define PB push_back
#define EB emplace_back
#define MP make_pair
#define FI first
#define SE second
#define PQ priority_queue

#define  ALL(v)  v.begin(),  v.end()
#define RALL(v) v.rbegin(), v.rend()
#define  FOR(it, v) for(auto it =  v.begin(); it !=  v.end(); ++it)
#define RFOR(it, v) for(auto it = v.rbegin(); it != v.rend(); ++it)

template<typename T> bool   setmin(T & a, T b) { if(b <  a) { a = b; return true; } else { return false; } }
template<typename T> bool   setmax(T & a, T b) { if(b >  a) { a = b; return true; } else { return false; } }
template<typename T> bool setmineq(T & a, T b) { if(b <= a) { a = b; return true; } else { return false; } }
template<typename T> bool setmaxeq(T & a, T b) { if(b >= a) { a = b; return true; } else { return false; } }
template<typename T> T gcd(T a, T b) { return (b == 0 ? a : gcd(b, a % b)); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }

// ---- ----

struct UnionFind {
	int s, num; // [0, s) の s 個の要素がある。num は非空集合の個数。
	vector<vector<int>> v;
	vector<int> find;
	
	UnionFind() { s = 0; }
	UnionFind(int s) { init(s); }
	void init(int arg_s) {
		num = s = arg_s;
		v.clear();
		find.clear();
		inc(i, s) { v.PB({i}); find.PB(i); }
	}
	bool unite(int x, int y) {
		assert(inID(x, 0, s) && inID(y, 0, s));
		if(find[x] == find[y]) { return false; }
		num--;
		if(v[find[x]].size() > v[find[y]].size()) { swap(x, y); }
		int fx = find[x];
		for(auto && e: v[fx]) { v[find[y]].PB(e); find[e] = find[y]; }
		v[fx].clear();
		return true;
	}
	
	
	void refresh(int w) {
		vector<vector<int>> v2;
		for(auto && ve: v) {
			vector<int> v3;
			for(auto && e: ve) { if(e >= w) { v3.PB(e - w); } }
			if(! v3.empty()) { v2.PB(v3); }
		}
		v = v2;
		inc(i, w) { v.PB({ w + i }); }
		
		vector<int> f2(w * 2);
		inc(i, v.size()) {
		inc(j, v[i].size()) {
			f2[v[i][j]] = i;
		}
		}
		find = f2;
	}
};

// ----

int h, w;
bool a[2][3000];

int id(int i, int j) { return w * i + j; }

int main() {
	cin >> h >> w;
	
	UnionFind uf(w * 2);
	int ans = 0;
	inc(i, h) {
		inc(j, w) {
			int b; cin >> b;
			a[0][j] = a[1][j];
			a[1][j] = (b == 1);
		}
		
		inc(j, w) { if(a[1][j]) { ans++; } }
		
		inc(j, w - 1) { if(a[1][j] && a[1][j + 1] && uf.unite(id(1, j), id(1, j + 1))) { ans--; } }
		inc(j, w    ) { if(a[0][j] && a[1][j    ] && uf.unite(id(0, j), id(1, j    ))) { ans--; } }
		
		uf.refresh(w);
	}
	
	cout << ans << endl;
	
	return 0;
}