#include <bits/stdc++.h>
using namespace std;

int h, w;
const int MAX = 3010;
int A[MAX][MAX];
int dx[4] = {-1, 1, 0, 0};
int dy[4] = {0, 0, -1, 1};
bool seen[MAX][MAX];

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    cin >> h >> w;

    for(int i = 0; i < h; i++){
        for(int j = 0; j < w; j++){
            cin >> A[i][j];
        }
    }

    int ans = 0;
    for(int i = 0; i < h; i++){
        for(int j = 0; j < w; j++){
            if(A[i][j] == 1 and !seen[i][j]){
                ans++;

                queue<pair<int, int>> q;
                seen[i][j] = true;
                q.push({i, j});
                while(!q.empty()){
                    pair<int, int> p = q.front();
                    q.pop();

                    for(int k = 0; k < 4; k++){
                        int nx = dx[k] + p.first;
                        int ny = dy[k] + p.second;
                        if(nx < 0 or nx >= h or ny < 0 or ny >= w) continue;
                        if(seen[nx][ny] or A[nx][ny] == 0) continue;
                        seen[nx][ny] = true;
                        q.push({nx, ny});
                    }
                }
            }
        }
    }
    cout << ans << endl;

    return 0;
}