//Code by Patcas Csaba

#include <vector>
#include <string> 
#include <set> 
#include <map> 
#include <queue> 
#include <bitset> 
#include <stack>
#include <list>

#include <numeric> 
#include <algorithm> 

#include <cstdio>
#include <fstream>
#include <iostream> 
#include <sstream> 
#include <iomanip>

#include <cctype>
#include <cmath> 
#include <ctime>
#include <cassert>

using namespace std;

#define LL long long
#define PII pair <int, int>
#define VB vector <bool>
#define VI vector <int>
#define VD vector <double>
#define VS vector <string>
#define VPII vector <pair <int, int> >
#define VVI vector < VI >
#define VVB vector < VB >

#define FORN(i, n) for(int i = 0; i < (n); ++i)
#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define FORD(i, a, b) for(int i = (a); i >= (b); --i)
#define REPEAT do{ 
#define UNTIL(x) }while(!(x)); 

#define SZ size()
#define BG begin() 
#define EN end() 
#define CL clear()
#define X first
#define Y second
#define RS resize
#define PB push_back
#define MP make_pair
#define ALL(x) x.begin(), x.end()

#define in_file "a.in"
#define out_file "a.out"

int n, m;
VVI dp;
VS a;

int solve(int i, int j)
{
	if (i > n || j > m) return 0;
	if (a[i][j] == '&') return dp[i][j] = 0;
	if (dp[i][j] != -1) return dp[i][j];
	int v1 = solve(i + 1, j);
	int v2 = solve(i, j + 1);
	return dp[i][j] = max(v1, v2) + 1;
}

int main()
{
	//Read data
	//freopen(in_file, "r", stdin);
	//freopen(out_file, "w", stdout);

	cin >> n >> m;
	a.RS(n + 1), dp.RS(n + 1, VI(m + 1, -1));
	FOR(i, 1, n)
	{
		a[i] += "X";
		FOR(j, 1, m)
		{
			
			char ch;
			cin >> ch;
			a[i] += ch;
		}
	}
	//Solve
	int sol = 0;
	FOR(i, 1, n)
		FOR(j, 1, m)
			if (dp[i][j] == -1) 
			{
				dp[i][j] = solve(i, j);
				sol = max(sol, dp[i][j]);
			}


	//Write data
	cout << sol;

	return 0;
}