#include<bits/stdc++.h>
using namespace std;
int n,m,ans;
char a[501][501];
int fx[4]={0,1,0,-1};
int fy[4]={1,0,-1,0};
void dfs(int x,int y){
//  cout<<x<<" "<<y<<endl;
    for(int i=0;i<=3;i++){
        int tx=fx[i]+x;
        int ty=fy[i]+y;
        if(tx>=1&&tx<=n&&ty>=1&&ty<=m&&a[tx][ty]=='0'){
            a[tx][ty]='*';
            dfs(tx,ty);
        }
    }
      
}
int main(){
    cin>>n>>m;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            cin>>a[i][j];
        }
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            if((i==1||j==1||i==n||j==m)&&a[i][j]=='0'){
                a[i][j]='*';
                dfs(i,j);
            }
        }
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            if(a[i][j]=='0'){
                ans++;
            }
        }
    }
    cout<<ans;
    return 0;
}
  
/**************************************************************
	Problem: 1913
	User: wangchenyu
	Language: C++
	Result: Accepted
	Time:28 ms
	Memory:2320 kb
****************************************************************/