#include<cstdio>
#include<queue>
#include<utility>
#include<cstring>
#include<stack>
#include<algorithm>
#include<cmath>
#include<iostream>
#include<map>
#define MAX_N 100001
#define INF_INT 2147483647
#define INF_LL 9223372036854775807
#define REP(i,n) for(int i=0;i<(int)(n);i++)
void init(int n);
int find(int n);
void unite(int x,int y);
bool same(int x, int y);
int dx[4] = {1,0,0,-1};
int dy[4] = {0,1,-1,0};
using namespace std;
typedef long long int ll;
typedef pair<ll,ll> P;
bool cmp_P(const P &a,const P &b){
  return a.second < b.second;
}
int main()
{
  int N,H,W,res=0;
  string pond[3001];
  bool visited[3001][3001];
  REP(i,3001)REP(j,3001)visited[i][j] = false;
  cin >> H >> W;
  REP(i,H)REP(j,W)cin >> pond[i][j];
  stack<P> stk;
  REP(i,H)REP(j,W){
    if(pond[i][j] == '1'){
      stk.push(P(j,i));
      while(!stk.empty()){
        P p = stk.top();stk.pop();
        pond[p.second][p.first] = '0';
        REP(i,4){
          int x = p.first+dx[i],y=p.second+dy[i];
          if(x < W && 0 <= x && y < H && y >= 0){
            if(visited[y][x] == false && pond[y][x] == '1'){
              stk.push(P(x,y));
              visited[y][x] = true;
            }
          }
        }
      }
      res++;
    }
  }
  
  cout << res << endl;
  return 0;
}

int par[MAX_N];
int ranks[MAX_N];

//n要素で初期化
void init(int n){
  REP(i,n){
    par[i] = i;
    ranks[i] = 0;
  }

}

//木の根を求める
int find(int x){
  if(par[x] == x){
    return x;
  }else{
    return par[x] = find(par[x]);
  }
}

void unite(int x,int y){
  x = find(x);
  y = find(y);
  if(x == y) return ;
  if(ranks[x] < ranks[y]){
    par[x] = y;
  }else{
    par[y] = x;
    if(ranks[x] == ranks[y]) ranks[x]++;
  }
}

bool same(int x, int y){
  return find(x) == find(y);
}