// Satellite Photographs.cpp : 定义控制台应用程序的入口点。

 //

 #include "stdafx.h"

 #include <iostream>

 #include <cstring>

 #include <algorithm>

 using namespace std;

 const int MAX = ;

 int n, m,ans, vis[MAX][MAX], dir[][] = { , , -, , , , , -};

 char map[MAX][MAX];

 void DFS(int x, int y, int num)

 {

     //cout << "x:" << x << "\ty:" << y << "\tnum:" << num << endl;

     ans = max(ans, num);

     for (int i = ; i < ; i++)

     {

         int nx = x + dir[i][];

         int ny = y + dir[i][];

         if (nx >=  && nx < n && ny >=  && ny < m && !vis[nx][ny] && map[nx][ny] == '*')

         {

             //cout << "nx:" << nx << "\tny:" << ny << endl;

             vis[nx][ny] = ;

             DFS(nx, ny, num + );

             vis[nx][ny] = ;

         }

     }

 }

 int main()

 {

         memset(vis, , sizeof(vis));

         memset(map, '\0', sizeof(map));

         ans = ;

         cin >> m >> n ;

         for (int i = ; i < n; i++)

             cin >> map[i];

         for (int i = ; i < n; i++)

         {

             for (int j = ; j < m; j++)

             {

                 if (map[i][j] == '*' && !vis[i][j])

                 {

                     vis[i][j] = ;

                     DFS(i, j, );

                     vis[i][j] = ;

                 }

             }

         }

         cout << ans << endl;

 }