#include <iostream>
#include <stdio.h>

using namespace std;

int n,m;
char d[101][101];



void read()
{ 
	int i,j;
	scanf("%d%d",&n,&m);
	for(i = 0; i < n; i++){
		getchar();
		for(j = 0; j < m; j++){
			char c = getchar();
			d[i][j] = c;
		}
	}


}
int solve(){
	int best = -1,max = 0,last = -1,li = 0;
	int i = 0,j = 0;
		while(/*j < m &&*/ i < n){
			if(max > best)
				best = max;
			if(d[i][j] != '&')
				max ++,j ++;
			if(i != li){
				int cj = j - 1;
				while(cj >= 0 && d[i][cj] != '&')
					cj--;
				if(cj > last)
					last = cj;
			}
			
			if(j == m || d[i][j] == '&')
			{
				if(max > best)
					best = max;
				i++;
				-- j;
			//	max ++;
				while(d[i][j] == '&' && j > last){
					--j,--max;
					if(i > 0 && d[i - 1][j] == '&')
						return best;
				}
				if(j < last)
					return best;
			}
			if(j < 0)
				return best;
			li = i;
		}
		
	return best;
}
int main()
{
//	freopen("f.in","r",stdin);
	read();
	printf("%d\n",solve());
	return 0;
}