#include<iostream>
#include<queue>
using namespace std;
#define N 25
struct point{
  int x;
  int y;
};
queue<point> q;
char a[N][N];//存地图
bool v[N][N];
int dx[4]={0,1,0,-1};
int dy[4]={1,0,-1,0};
int w,h,cnt;
point start;
int main()
{
 
  //w列 h行 格子为h*w规格棋盘
  cin>>w>>h;
  for(int i=0;i<h;i++)
     for(int j=0;j<w;j++){
      cin>>a[i][j];
      if(a[i][j]=='@'){
          start.x=i;
          start.y=j;
      }
     }
  q.push(start);
  v[start.x][start.y]=true;
  while(!q.empty()){
    point header=q.front();
    for(int i=0;i<4;i++){
      point temper=header; 
      temper.x+=dx[i];
      temper.y+=dy[i];
      if(a[temper.x][temper.y]=='.'&&!v[temper.x][temper.y])q.push(temper);
      v[temper.x][temper.y]=true;
    }	
    q.pop();
    cnt++;
  }
cout<<cnt<<endl;
  return 0;
}

w, h = map(int, input().split())
m = []
s = (-1, -1)
for i in range(h):
  line = input()
  m.append(line)
  if("@" in line):
    s = (i, line.index("@"))
ans = 1
direct = [(1, 0), (0, 1), (-1, 0), (0, -1)]
vis = [[True]*w for _ in range(h)]
def check(x, y):
  if(x<0 or y<0 or x>=h or y>=w): return False
  if(not vis[x][y]): return False
  if(m[x][y]!='.'): return False
  return True
ans = 1
def dfs(x, y):
  global ans
  for dx, dy in direct:
    nx = x + dx
    ny = y + dy
    if(check(nx, ny)):
      vis[nx][ny] = False
      ans+=1
      dfs(nx, ny)
dfs(*s)
print(ans)

bfs

from collections import deque
ans = 1
def bfs(s):
    global ans
    q = deque()
    q.append(s)
    while (len(q) != 0):
        tx, ty = q.popleft()
        for dx, dy in direct:
            nx = tx + dx
            ny = ty + dy
            if (check(nx, ny)):
                vis[nx][ny] = False
                ans += 1
                q.append((nx, ny))
bfs(s)
print(ans)

#include<iostream> #include<vector> #include<string> using namespace std; int W,H,ans=1; vector<vector <string> > A; bool vit[20][20]; void dfs(int x,int y){

if(y+1<W&&A[x][y+1]=="."&&!vit[x][y+1])
{
	ans++;
	vit[x][y+1]=1;
	dfs(x,y+1);
}
if(x+1<H&&A[x+1][y]!="#"&&!vit[x+1][y])
{
	ans++;
	vit[x+1][y]=1;
	dfs(x+1,y);
}
if(y-1>=0&&A[x][y-1]!="#"&&!vit[x][y-1])
{
	ans++;
	vit[x][y-1]=1;
	dfs(x,y-1);
}
if(x-1>=0&&A[x-1][y]=="."&&!vit[x-1][y])
{
	ans++;
	vit[x-1][y]=1;
	dfs(x-1,y);
}

// return; } int main(){ char ch; int x,y; cin>>W>>H; vector<vector <string> > B(H,vector<string> (W)); for(int i=0;i<H;i++) { for(int j=0;j<W;j++) { cin>>ch; B[i][j]=ch; if(B[i][j]=="@") { x=i;y=j; vit[i][j]=1; } } } A=B; dfs(x,y); cout<<ans<<endl; return 0; }

#include<bits/stdc++.h>
using namespace std;
int n,m,ans=0;
char f[25][25];
int dx[4]={0,0,-1,1};
int dy[4]={-1,1,0,0};
void dfs(int x,int y){
	if(f[x][y]=='#'){
		return ;
	}
	f[x][y]='#';
	ans++;
	for(int i=0;i<4;i++){
		int nx=x+dx[i];
		int ny=y+dy[i];
		if(f[nx][ny]=='.'&&nx>0&&nx<=m&&ny>0&&ny<=n){
			dfs(nx,ny);
		}
	}
}
int main(){
	cin>>n>>m;
	for(int i=1;i<=m;i++){
		for(int j=1;j<=n;j++){
			cin>>f[i][j];
		}
	}
	for(int i=1;i<=m;i++){
		for(int j=1;j<=n;j++){
			if(f[i][j]=='@'){
				dfs(i,j);
			}
		}
	}
	cout<<ans;
	return 0;
}