#include <bits/stdc++.h>
using namespace std;
const pair<int, int> DXY[] = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};

struct dsu{
    vector<int> par, sz;
    dsu(int n) : par(n), sz(n, 1){
        iota(par.begin(), par.end(), 0);
    }
    int root(int x){
        if (par[x] == x) return x;
        return par[x] = root(par[x]);
    }
    bool merge(int x, int y){
        x = root(x), y = root(y);
        if (x == y) return false;
        if (sz[x] < sz[y]) swap(x, y);
        par[y] = x, sz[x] += sz[y];
        return true;
    }
    bool same(int x, int y){
        return root(x) == root(y);
    }
    int size(int x){
        return sz[root(x)];
    }
};

int main(){
    int H, W;
    cin >> H >> W;
    vector<vector<int>> A(H, vector<int>(W));
    for (int i = 0; i < H; i++){
        for (int j = 0; j < W; j++){
            cin >> A[i][j];
        }
    }

    auto id = [&](int i, int j){ return W*i+j; };
    dsu uf(H*W);
    for (int i = 0; i < H; i++){
        for (int j = 0; j < W; j++){
            for (auto [dx, dy] : DXY){
                int nx = i+dx, ny = j+dy;
                if (nx < 0 || H <= nx || ny < 0 || W <= ny) continue;
                if (A[i][j] && A[nx][ny]) uf.merge(id(i, j), id(nx, ny));
            }
        }
    }

    set<int> roots;
    for (int i = 0; i < H; i++){
        for (int j = 0; j < W; j++){
            if (A[i][j]) roots.insert(uf.root(id(i, j)));
        }
    }

    cout << roots.size() << endl;
}