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

bool A[10000000];
int comp[10000000];

int main()
{
    int H, W;
    cin >> H >> W;
    H += 2;
    W += 2;
    for (int i = 1; i <= H - 2; i++)
    {
        for (int j = 1; j <= W - 2; j++)
        {
            cin >> A[W * i + j];
        }
    }
    int n = 1;
    for (int i = 0; i < H * W; i++)
    {
        if ((not A[i]) or (comp[i]))
        {
            continue;
        }
        comp[i] = n;
        queue<int> q;
        q.push(i);
        while (!q.empty())
        {
            int v = q.front();
            q.pop();

            int dx[] = {1, -1, W, -W};
            for (i = 0; i < 4; i++)
            {
                int w = v + dx[i];
                if ((not A[w]) or (comp[w]))
                {
                    continue;
                }
                comp[w] = n;
                q.push(w);
            }
        }
        n++;
    }
    cout << n - 1 << endl;
}