#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <stack>
#include <queue>
#include <map>
#include <unordered_map>
#include <cassert>
using namespace std;
using i64 = int64_t;
constexpr i64 mod = 1e9 + 7;
using vi = vector<i64>;
using vvi = vector<vi>;
using ii = pair<i64, i64>;
using vii = vector<ii>;

int h, w;
bool board[3000][3000];

bool is_valid(ii p) {
    int x = p.first, y = p.second;
    return 0 <= x && x < h && 0 <= y && y < w;
}

void dfs(ii p) {
    int x = p.first, y = p.second;
    if (is_valid(p) && board[x][y]) {
        board[x][y] = 0;
        dfs(ii(x + 1, y));
        dfs(ii(x - 1, y));
        dfs(ii(x, y + 1));
        dfs(ii(x, y - 1));
    }
}

int cnt;

int main() {
    cin >> h >> w;
    for (int i = 0; i < h; i++) {
        for (int j = 0; j < w; j++) {
            cin >> board[i][j];
        }
    }
    
    for (int i = 0; i < h; i++) {
        for (int j = 0; j < w; j++) {
            if (board[i][j]) {
                dfs(ii(i, j));
                cnt++;
            }
        }
    }
    
    cout << cnt << endl;
}