#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int, int> P;
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};

int H, W;
int A[3100][3100];

void bfs(int sx, int sy) {
    A[sx][sy] = 1;
    queue<P> q;
    q.push(P(sx, sy));
    
    while (q.size()) {
        P p = q.front(); q.pop();
        int cx = p.first;
        int cy = p.second;
        
        for (int i=0; i<4; i++) {
            int nx = cx + dx[i];
            int ny = cy + dy[i];
            
            if (0<=nx && nx<H && 0<=ny && ny<W && A[nx][ny]==1) {
                A[nx][ny] = 0;
                q.push(P(nx, ny));
            }
        }
    }
    
    return;
}

signed main() {
    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) {
                ans++;
                bfs(i, j);
            }
        }
    }
    
    cout << ans << endl;
}