#include "bits/stdc++.h"
#define MAXN 300009
#define INF 1000000007
#define mp(x,y) make_pair(x,y)
#define all(v) v.begin(),v.end()
#define pb(x) push_back(x)
#define wr cout<<"----------------"<<endl;
#define ppb() pop_back()
#define tr(ii,c) for(__typeof((c).begin()) ii=(c).begin();ii!=(c).end();ii++)
#define ff first
#define ss second
#define my_little_dodge 46
#define debug(x)  cerr<< #x <<" = "<< x<<endl;
using namespace std;

typedef long long ll;
typedef pair<int,int> PII;
template<class T>bool umin(T& a,T b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool umax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
int fup[MAXN],tin[MAXN],TIM,ans;
vector<int>adj[MAXN];
stack<int>st;
char arr[505][505];
void dfs(int nd,int pr){
	st.push(nd);
	fup[nd]=tin[nd]=++TIM;
	for(int i=0;i<int(adj[nd].size());i++){
		int to=adj[nd][i];
		if(to==pr)
			continue;
		if(!tin[to]){
			dfs(to,nd);
			umin(fup[nd],fup[to]);
		}	
		else
			umin(fup[nd],tin[to]);
	}	
	if(fup[nd]==tin[nd]){
		int aux,sz=0;
		do{
			aux=st.top();st.pop();
			sz++;
		}while(aux!=nd);
		ans+=sz==1;
	}
}
int main(){
    //~ freopen("file.in", "r", stdin);
    int n,m;
    scanf("%d%d",&n,&m);
    for(int i=1;i<=n;i++)
		for(int j=1;j<=m;j++)
			scanf(" %c",&arr[i][j]);
	for(int i=1;i<=n;i++)
		for(int j=1;j<=m;j++){
			if(arr[i][j]=='0')
				continue;
			if(i>1 and arr[i-1][j]=='1'){
				adj[(i-2)*m+j].pb((i-1)*m+j);
				adj[(i-1)*m+j].pb((i-2)*m+j);
			}
			if(j>1 and arr[i][j-1]=='1'){
				adj[(i-1)*m+j-1].pb((i-1)*m+j);
				adj[(i-1)*m+j].pb((i-1)*m+j-1);
			}	
		}
	for(int i=1;i<=n*m;i++)
		if(!tin[i])
			dfs(i,-1);
	printf("%d\n",n*m-ans);		
	return 0;
}