#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

char a[102][102];
int n, m;
int dp[103][103];
int main() {
//    freopen ("b.in", "r", stdin);
    scanf ("%d %d\n", &n, &m);
    int i, j;
    for (i = 1; i <= n; ++i)
        scanf ("%s\n", a[i] + 1);
    dp[1][1] = 1;
    int  mx = 1;
    for (i = 1; i <= n; ++i)
        for (j = 1; j <= m; ++j) {
            if (i == 1 && j == 1)
                continue;
            if (a[i][j] == '&')
                continue;
            dp[i][j] = -0x3f3f3f3f;
            if (i - 1 >= 1 && a[i - 1][j] != '&')
                dp[i][j] = max(dp[i][j], dp[i - 1][j] + 1);
            if (j - 1 >= 1 && a[i][j - 1] != '&')
                dp[i][j] = max(dp[i][j], dp[i][j - 1] + 1);
            if (mx < dp[i][j])
                mx = dp[i][j];
        }
    printf ("%d\n", mx);
}