#include <cstdio>
#include <iostream>
#include <string>
#include <sstream>
#include <stack>
#include <algorithm>
#include <cmath>
#include <queue>
#include <map>
#include <set>
#include <cstdlib>
#include <bitset>
#include <tuple>
#include <assert.h>
#include <deque>
#include <bitset>
#include <iomanip>
#include <limits>
#include <chrono>
#include <random>
#include <array>
#include <unordered_map>
#include <functional>
#include <complex>

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

const long long MAX = 5100000;
const long long INF = 1LL << 60;
const long long mod = 1000000007LL;
//const long long mod = 998244353LL;

using namespace std;
typedef unsigned long long ull;
typedef long long ll;

ll H, W;
vector<vector<bool>> vi;
ll dh[4] = { 1,0,-1,0 };
ll dw[4] = { 0,1,0,-1 };
void dfs(ll h, ll w) {
	vi[h][w] = 0;
	for (ll i = 0; i < 4; i++) {
		ll nh = h + dh[i];
		ll nw = w + dw[i];
		if (nh < 0 || nh >= H || nw < 0 || nw >= W) continue;
		if (vi[nh][nw]) {
			dfs(nh, nw);
			vi[nh][nw]=false;
		}
	}
}

int main()
{
	/*
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	*/
	scanf("%lld %lld", &H, &W);
	vi = vector<vector<bool>>(H, vector<bool>(W));
	for (ll i = 0; i < H; i++) for (ll j = 0; j < W; j++) { int x; scanf("%d", &x); vi[i][j] = x; }

	ll res = 0;
	for (ll i = 0; i < H; i++) {
		for (ll j = 0; j < W; j++) {
			if (vi[i][j]) {
				dfs(i, j);
				res++;
			}
		}
	}
	cout << res << endl;
	return 0;
}