#include<iostream>
#include<cstdio>
#include<cstring>
#include <cstdlib>  
#include <math.h>
#include <cmath>   
#include<cctype>
#include<string>
#include<set>
#include<iomanip>
#include <map>
#include<algorithm>
#include <functional>
#include<vector>
#include<climits>
#include<stack>
#include<queue>
#include <deque>
#include <climits>
#include <typeinfo>
#include <utility> 
#define all(x) (x).begin(),(x).end()
#define rep(i,m,n) for(int i = m;i < n;++i)
#define pb push_back
#define fore(i,a) for(auto &i:a)
#define rrep(i,m,n) for(int i = m;i >= n;--i)
#define INF INT_MAX/2
using namespace std;
using ll = long long;
using R = double;
using Data = pair<ll, vector<int>>;
const ll MOD = 1e9 + 7;
const ll inf = 1LL << 50;
struct edge { ll from; ll to; ll cost; };

vector<vector<char>>mp(3030,vector<char>(3030));
int used[3030][3030];
int h, w;

void bfs(int x, int y) {

	used[y][x] = 1;
	queue<pair<int, int>>q;
	q.push({x,y});

	while (!q.empty()) {
		auto now = q.front();
		q.pop();
		int xnow = now.first;
		int ynow = now.second;

		int dx[4] = { -1,0,1,0 };
		int dy[4] = { 0,-1,0,1 };
		rep(i, 0, 4) {
			int _x = xnow + dx[i];
			int _y = ynow + dy[i];
			if (0 <= _x && _x <= w - 1 && 0 <= _y && _y <= h - 1) {
				if (used[_y][_x] == 0 && mp[_y][_x] == '1') {
					q.push({ _x,_y });
					used[_y][_x] = 1;
				}
			}
		}
	}
	return;
}

int main() {
	cin >> h >> w;

	rep(i, 0, h)rep(j,0,w)cin >> mp[i][j];

	int ans = 0;
	rep(i, 0, h)rep(j,0,w){
		if (mp[i][j] == '1' && used[i][j] == 0) {
			bfs(j,i);
			ans++;
		}
	}
	cout << ans << endl;

	return 0;
}