#include <algorithm>
#include <complex>
#include <cstdlib>
#include <ctime>
#include <iomanip>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>

using namespace std;
#define SAY_YES cout << "YES" << endl;
#define SAY_Yes cout << "Yes" << endl;
#define SAY_NO cout << "NO" << endl;
#define SAY_No cout << "No" << endl;
#define IFYES(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "YES" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "NO" << endl;  \
    }
#define IFYes(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "Yes" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "No" << endl;  \
    }
#define IFyes(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "yes" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "no" << endl;  \
    }
#define DEBUG_OUTPUT_ARRAY(XXX, ONE)                            \
    for (int i = 0; i < (ONE); i++)                             \
    {                                                           \
        cout << "DEBUG: i = " << i << " -> " << XXX[i] << endl; \
    }
#define DEBUG_OUTPUT_ARRAY2(XXX, ONE, TWO)                             \
    for (int i = 0; i < (ONE); i++)                                    \
    {                                                                  \
        cout << "<<< i = " << i << " >>>" << endl;                     \
        for (int j = 0; j < (TWO); j++)                                \
        {                                                              \
            cout << "DEBUG: j = " << j << " -> " << XXX[i][j] << endl; \
        }                                                              \
    }
#define DEBUG_OUTPUT_ARRAY2_BOX(XXX, ONE, TWO) \
    for (int i = 0; i < (ONE); i++)            \
    {                                          \
        cout << i << "  ";                     \
        for (int j = 0; j < (TWO); j++)        \
        {                                      \
            cout << XXX[i][j] << " ";          \
        }                                      \
        cout << endl;                          \
    }

typedef pair<long long int, long long int> pll;


const long long int mod = 1000000007;
const long long int INF = 99999999999999999;

long long int R,C,sy,sx,gy,gx,used[55][55]={},res[55][55]={},tot=0;
char c[55][55];
queue<pll>que;
int main()
{
    cout << fixed << setprecision(18);
	cin>>R>>C;
	for(int i=1;i<=R;i++){
		for(int j=1;j<=C;j++){
			cin>>c[i][j];
			res[i][j]=INF;
            if(c[i][j]=='.'){tot++;}
		}
	}
    for(long long int i = 0; i <= R; i++){
        c[i][0]='#';
        c[i][C+1]='#';
    }
    for(long long int i = 0; i <= C; i++){
        c[0][i]='#';
        c[R+1][i]='#';
    }
	que.push({1,1});
	res[1][1]=1;
	while(!que.empty()){
		if(c[que.front().first][que.front().second]=='#'||used[que.front().first][que.front().second]){
			que.pop();
			continue;
		}
		
		used[que.front().first][que.front().second]=true;
        
		que.push({que.front().first+1,que.front().second});
		que.push({que.front().first-1,que.front().second});
		que.push({que.front().first,que.front().second+1});
		que.push({que.front().first,que.front().second-1});
		
		
		res[que.front().first+1][que.front().second]=min(res[que.front().first+1][que.front().second],res[que.front().first][que.front().second]+1);
		res[que.front().first-1][que.front().second]=min(res[que.front().first-1][que.front().second],res[que.front().first][que.front().second]+1);
		res[que.front().first][que.front().second+1]=min(res[que.front().first][que.front().second+1],res[que.front().first][que.front().second]+1);
		res[que.front().first][que.front().second-1]=min(res[que.front().first][que.front().second-1],res[que.front().first][que.front().second]+1);
	}
    if(res[R][C]==INF){res[R][C]=tot+1;}
	cout<<tot-res[R][C]<<endl;
}



Measured memory_bytes: 256