#include <cstdio>
#include <cstring>
using namespace std;
int n,m,i;
bool viz[105][105];
char drum[105][105];
int coada[2][10005];
int val[105][105];
int ic,sf;
inline int coadax()
{
    int maxdrum=ic=sf=1;
    coada[0][1]=val[1][0]=1;
    coada[1][1]=0;
    while (ic<=sf)
    {
        int x=coada[0][ic],y=coada[1][ic]; viz[x][y]=1;
        while (drum[x+1][y]!='&' && !viz[x+1][y] && x+1<=n)
        {
            coada[0][++sf]=x+1;
            coada[1][sf]=y;
            viz[x+1][y]=1;
            val[x+1][y]=val[x][y]+1;
            if (val[x+1][y]>maxdrum) maxdrum=val[x+1][y];
        }
        while (drum[x-1][y]!='&' && !viz[x-1][y] && x-1>0)
        {
            coada[0][++sf]=x-1;
            coada[1][sf]=y;
            viz[x-1][y]=1;
            val[x-1][y]=val[x][y]+1;
            if (val[x-1][y]>maxdrum) maxdrum=val[x-1][y];
        }
        while (drum[x][y+1]!='&' && !viz[x][y+1] && y+1<m)
        {
            coada[0][++sf]=x;
            coada[1][sf]=y+1;
            viz[x][y+1]=1;
            val[x][y+1]=val[x][y]+1;
            if (val[x][y+1]>maxdrum) maxdrum=val[x][y+1];
        }
        while (drum[x+1][y-1]!='&' && !viz[x][y-1] && y-1>=0)
        {
            coada[0][++sf]=x;
            coada[1][sf]=y-1;
            viz[x][y-1]=1;
            val[x][y-1]=val[x][y]+1;
            if (val[x][y-1]>maxdrum) maxdrum=val[x][y-1];
        }
        ic++;
    }
    return maxdrum;
}
int main()
{
    scanf("%d %d",&n,&m);
    for (i=1;i<=n;i++)
        scanf("%s",drum[i]);
    printf("%d",coadax());
    return 0;
}