class Unionfind {
public:
    vector<int> data;
    Unionfind(size_t size) : data(size, -1) { }
    bool connect(size_t x, size_t y) {
        x = root(x); y = root(y);
        if (x != y) {
            if (data[y] < data[x]) swap(x, y);
            data[x] += data[y]; data[y] = (int)x;
        }
        return x != y;
    }
    inline bool same(size_t x, size_t y) {
        return root(x) == root(y);
    }
    inline size_t root(size_t x) {
        return (size_t)(data[x] < 0 ? x : data[x] = root(data[x]));
    }
    inline int size(size_t x) {
        return -data[root(x)];
    }
};

int H,W,HW;
{
    rd(H,W); HW = H*W;
    Unionfind uf(HW+1);
    register int cnt;cnt = HW+1;
    REP(p, HW){
        int c;rd(c);
        if (c == 0)
            cnt -= uf.connect(p, HW);
        else{
            if (W<=p  && !uf.same(p-W, HW)) cnt -= uf.connect(p, p-W);
            if (p%W>0 && !uf.same(p-1, HW)) cnt -= uf.connect(p, p-1);
        }
    }
    wt(cnt-1);
}