#include <iostream>
#include <cmath>
#include <algorithm>

using namespace std;

string a[150];
int n, m;
int sol[150][150];

void readData() {
    cin >> n >> m;
    for (int i = 0; i < n; ++i)
        cin >> a[i];
}

int solve() {
    sol[0][0] = a[0][0] == '&' ? 0 : 1;
    int max = sol[0][0];

    for (int i = 0; i < n; ++i)
        for (int j = 0; j < m; ++j) {
            if (i == 0 && j == 0) continue;
            if (a[i][j] == '&') { sol[i][j] == -1000000; continue; }

            sol[i][j] = 0;
            if (i > 0)
                sol[i][j] = 1 + sol[i-1][j];
            if (j > 0)
                sol[i][j] = std::max(sol[i][j], 1 + sol[i][j-1]);

            if (sol[i][j] > max)
                max = sol[i][j]; 
        }
 
    return max;
}

int main() {
    readData();
    cout << solve() << endl;
    return 0;
}