#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=int(a);i<int(b);++i)
using namespace std;
typedef long long ll;
int INF = (1LL << 30) - 1;
int MOD = 1e9+7;
const int MAX_N = 9000000;
int par[MAX_N];
bool V[3000][3000];
struct UnionFind{
    //int par[MAX_N];
    void init(int n){
        for(int i = 0;i < n;i++)par[i] = i;
    }
    int root(int x){
        if(par[x] == x)return x;
        else return par[x] = root(par[x]);
    }
    bool same(int x,int y){
        return root(x) == root(y);
    }
    void unite(int x,int y){
        x = root(x);
        y = root(y);
        if(x == y)return;
        par[y] = x;
    }
};

main(){
    int H,W;    
    int dx[] = {1,-1,0,0}, dy[] = {0,0,1,-1};
    
    cin >> H >> W;
    rep(i,0,H)rep(j,0,W)cin >> V[i][j];

    UnionFind uf;
    uf.init(H*W);//(i,j) → i*W + j

    rep(i,0,H)rep(j,0,W){
        if(V[i][j]){
            rep(k,0,4){
                int x = dx[k] + j, y = dy[k] + i;
                if(x < 0 || x >= W || y < 0 || y >= H)continue;
                if(V[y][x])uf.unite(i * W + j, y * W + x);
            }
        }
    }
    set<int> st;
    rep(i,0,H)rep(j,0,W)if(V[i][j])st.insert(uf.root(i * W + j));
    cout << st.size() << endl;
}