#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n);i++)
#define sz(x) int(x.size())
typedef long long ll;
typedef pair<int,int> P;

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

int main(){
  int h, w;
  cin >> h >> w;
  vector<vector<int>> a(h,vector<int>(w));
  rep(i,h) rep(j,w) cin >> a[i][j];

  auto bfs = [&](int y, int x) {
    queue<P> que;
    que.push({y,x});
    a[y][x] = 0;
    while (!que.empty()) {
      P p = que.front(); que.pop();
      rep(i,4) {
        int ny = p.first + dy[i], nx = p.second + dx[i];
        if (ny < 0 || nx < 0 || ny >= h || nx >= w) continue;
        if (a[ny][nx] == 0) continue;
        que.push({ny,nx});
        a[ny][nx] = 0;
      }
    }
  };
  int res = 0;
  rep(i,h) rep(j,w) if (a[i][j] == 1) bfs(i,j), res++;
  cout << res << endl;
  return 0;
}