#include <bits/stdc++.h>
using namespace std;
int dx[4] = {0, 1, 0, -1};
int dy[4] = {-1, 0, 1, 0};
int n, m, ans = 0, s = 0;
char st[110];
bool a[1100][90];
void dfs(int x, int y)
{
    s++;
    a[x][y] = false;
    for (int i = 0; i <= 3; i++)
    {
        int xx = x + dx[i];
        int yy = y + dy[i];
        if (xx >= 1 && xx <= n && yy >= 1 && yy <= m)
            if (a[xx][yy] == true)
                dfs(xx, yy);
    }
}
int main()
{
    memset(a, false, sizeof(a));
    scanf("%d%d", &m, &n);
    for (int i = 1; i <= n; i++)
    {
        scanf("%s", st + 1);
        for (int j = 1; j <= m; j++)
            if (st[j] == '*')
                a[i][j] = true;
    }

    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
            if (a[i][j] == true)
            {
                s = 0;
                dfs(i, j);
                ans = max(ans, s);
            }

    printf("%d", ans);
    return 0;
}