#define  _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <map>
#include <queue>
#include <vector>
#include <cmath>
#include <set>
#include <algorithm>
#include <climits>
#include <string>
#include <stack>
using namespace std;
using ll = long long;
const int N = 55;
int n, m;
int vis[N][N];
string s[N];
const int tx[] = { 1,-1,0,0 }, ty[] = { 0,0,1,-1 };
vector<pair<int, int>>ve1, ve2;
void dfs1(int x, int y) {
    if (x < 0 || y < 0 || x >= n || y >= m) return;
    if (vis[x][y]||s[x][y]=='.') return;
    vis[x][y] = 1;
    ve1.push_back({ x,y });
    for (int i = 0; i < 4; i++) {
        dfs1(x + tx[i], y + ty[i]);
    }
}
int mini = 50000;

void solve() {
    int i,flag=0, j;
    cin >> n >> m;
    for (i = 0; i < n; i++) {
        cin >> s[i];
    }
    for (i = 0; i < n; i++) {
        for (j = 0; j < m; j++) {
            if (s[i][j] == 'X') {
                if(flag==0)dfs1(i,j);
                flag = 1;
                if (vis[i][j] == 0) ve2.push_back({ i,j });

            }
        }
    }
    for (i = 0; i < ve1.size(); i++) {
        for (j = 0; j < ve2.size(); j++) {
            int t = abs(ve1[i].first - ve2[j].first) + abs(ve1[i].second - ve2[j].second);
            if (t < mini) {
                mini = t;
            }
        }
    }
    cout << mini-1 << endl;
}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int t;
    t = 1;
    //cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}