#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <queue>
#include <string>
#include <map>
#include <set>
#include <stack>
#include <tuple>
#include <deque>
#include <array>
#include <numeric>
#include <bitset>
#include <iomanip>
#include <cassert>
#include <chrono>
#include <random>
#include <limits>
#include <iterator>
#include <functional>
#include <sstream>
#include <fstream>
#include <complex>
#include <cstring>
#include <unordered_map>
using namespace std;

using ll = long long;
using P = pair<int, int>;
constexpr int INF = 1001001001;
constexpr int mod = 1000000007;
// constexpr int mod = 998244353;

template<class T>
inline bool chmax(T& x, T y){
    if(x < y){
        x = y;
        return true;
    }
    return false;
}
template<class T>
inline bool chmin(T& x, T y){
    if(x > y){
        x = y;
        return true;
    }
    return false;
}

constexpr int dx[4] = {1, 0, -1, 0};
constexpr int dy[4] = {0, 1, 0, -1};

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    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];
        }
    }
    vector<vector<bool>> used(H, vector<bool>(W));
    int ans = 0;
    for(int i = 0; i < H; ++i){
        for(int j = 0; j < W; ++j){
            if(used[i][j] || A[i][j] == 0)  continue;
            ans += 1;
            queue<P> que;
            que.emplace(i, j);
            used[i][j] = true;
            while(!que.empty()){
                auto [x, y] = que.front();
                que.pop();
                for(int k = 0; k < 4; ++k){
                    int nx = x + dx[k], ny = y + dy[k];
                    if(nx < 0 || nx >= H || ny < 0 || ny >= W)  continue;
                    if(used[nx][ny] || A[nx][ny] == 0)  continue;
                    que.emplace(nx, ny);
                    used[nx][ny] = true;
                }
            }
        }
    }
    cout << ans << '\n';

    return 0;
}