#include <cassert>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <limits.h>
#include <map>
#include <queue>
#include <set>
#include <string.h>
#include <vector>

using namespace std;
typedef long long ll;

const int MAX_H = 3000;
const int MAX_W = 3000;
const int DY[4] = {-1, 0, 1, 0};
const int DX[4] = {0, 1, 0, -1};

int H, W;
int A[MAX_H][MAX_W];

void f(int y, int x) {
  queue<int> que;
  que.push(y * W + x);

  while (!que.empty()) {
    int z = que.front();
    int y = z / W;
    int x = z % W;
    A[y][x] = 0;
    que.pop();

    for (int i = 0; i < 4; ++i) {
      int ny = y + DY[i];
      int nx = x + DX[i];
      int nz = ny * W + nx;
      if (ny < 0 || nx < 0 || H <= ny || W <= nx) continue;
      if (A[ny][nx] == 0) continue;

      que.push(nz);
    }
  }
}

int main() {
  cin >> H >> W;
  fprintf(stderr, "H: %d, W: %d\n", H, W);

  for (int y = 0; y < H; ++y) {
    for (int x = 0; x < W; ++x) {
      cin >> A[y][x];
    }
  }

  int ans = 0;

  for (int y = 0; y < H; ++y) {
    for (int x = 0; x < W; ++x) {
      if (A[y][x] == 0) continue;

      ++ans;
      f(y, x);
    }
  }

  cout << ans << endl;

  return 0;
}