#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cmath>
#include<cctype>
#include<math.h>
#include<string>
#include<string.h>
#include<stack>
#include<queue>
#include<vector>
#include<utility>
#include<set>
#include<map>
#include<stdlib.h>
#include<iomanip>

using namespace std;

#define ll long long
#define ld long double
#define EPS 0.0000000001
#define INF 1e9
#define LINF (ll)INF*INF
#define MOD 1000000007
#define rep(i,n) for(int i=0;i<(n);i++)
#define loop(i,a,n) for(int i=a;i<(n);i++)
#define all(in) in.begin(),in.end()
#define shosu(x) fixed<<setprecision(x)

#define int ll //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

typedef vector<int> vi;
typedef vector<string> vs;
typedef pair<int,int> pii;
typedef vector<pii> vp;

int gcd(int a, int b){
    if(b==0) return a;
    return gcd(b,a%b);
}
int lcm(int a, int b){
    return a/gcd(a,b)*b;
}

int dx[] = {0, 1, 0, -1};
int dy[] = {1, 0, -1, 0};

vp v;
vector<vi> a,used;
queue<pii> q;

signed main(void) {
    int h,w;
    cin >> h >> w;
    a = used = vector<vi> (h,vi(w));
    rep(i,h)rep(j,w)cin >> a[i][j];
    int ans = 0;
    rep(i,h)rep(j,w)if(a[i][j]){
        q.push(pii(i,j));
        used[i][j]++;
        while(q.size()){
            int x = q.front().first;
            int y = q.front().second;
            v.push_back(pii(x,y));
            q.pop();
            rep(k,4){
                int nx = x + dx[k];
                int ny = y + dy[k];
                if(nx < 0 || nx >= h || ny < 0 || ny >= w)continue;
                if(a[nx][ny] == 0 || used[nx][ny])continue;
                used[nx][ny]++;
                q.push(pii(nx,ny));
            }
        }
        rep(k,v.size()){
            a[v[k].first][v[k].second]--;
            used[v[k].first][v[k].second]--;
        }
        ans++;
        v.clear();
    }
    cout << ans << endl;
}