#include<bits/stdc++.h>
using namespace std;
int n,m,tx[4]={-1,0,1,0},ty[4]={0,-1,0,1},num;
char a[505][505];
 
void bfs(int x,int y){
    a[x][y]='*';
    for(int i=0;i<4;i++){
        int dx=x+tx[i],dy=y+ty[i];
        if(dx>=0&&dx<=n+1&&dy>=0&&dy<=m+1&&a[dx][dy]!='*') bfs(dx,dy);
    }
}
 
int main(){
    cin>>n>>m;
    for(int i=1;i<=n;i++)
        for(int j=1;j<=m;j++)
            cin>>a[i][j];
    bfs(0,0);
    for(int i=1;i<=n;i++)
        for(int j=1;j<=m;j++)
            if(a[i][j]=='0') num++;
    cout<<num;
}
/**************************************************************
	Problem: 1913
	User: panyuchen
	Language: C++
	Result: Accepted
	Time:25 ms
	Memory:2324 kb
****************************************************************/