#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <iostream>
#include <vector>
#include <string>
#include <sstream>
#include <algorithm>
#include <utility>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <deque>
#include <functional>

using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pii;
typedef vector<pii> vpii;

#define fst first
#define scd second
#define PB push_back
#define MP make_pair
#define rep(i,x) for(int i=0;i<(x);++i)
#define rep1(i,x) for(int i=1;i<=(x);++i)
#define rrep(i,x) for(int i=(x)-1;i>=0;--i)
#define rrep1(i,x) for(int i=(x);i>=1;--i)
#define FOR(i,a,x) for(int i=(a);i<(x);++i)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()

#define omajinai ios::sync_with_stdio(false);cin.tie(0)

template<typename T>bool chmax(T&a,T b){if(a<b){a=b;return true;}return false;}
template<typename T>bool chmin(T&a,T b){if(a>b){a=b;return true;}return false;}
template<typename T>T get(){T a;cin>>a;return a;}
template<typename T>T rev(T a){reverse(all(a));return a;}
template<typename T>istream&operator>>(istream&is,vector<T>&vec){rep(i,vec.size())is>>vec[i];return is;}
template<typename T>vector<T>&sort(vector<T>&a){sort(all(a));return a;}

const int inf = 1e9;
const ll linf = 3e18;
const double eps = 1e-9;

int dx[4] = {-1, 0, 1, 0}, dy[4] = {0, -1, 0, 1};

int W, H;
char C[22][22];
int d[2][22][22];

bool inside(int y, int x)
{
    return (0 <= y && y < H && 0 <= x && x < W);
}

void dfs_fill(int t, int y, int x)
{
    C[y][x] = t + '0';
    d[t][y][x] = 0;

    rep(i, 4) {
        int ny = y + dy[i], nx = x + dx[i];
        if (!inside(ny, nx)) continue;
        if (C[ny][nx] == '.') dfs_fill(t, ny, nx);
    }
}

void bfs_shortest_path(int t, int y, int x)
{
    queue<pii> q;
    q.push(pii(y, x));
    d[t][y][x] = 0;

    while (q.size()) {
        pii p = q.front(); q.pop();
        rep(i, 4) {
            int ny = p.fst + dy[i], nx = p.scd + dx[i];
            if (C[ny][nx] == '#') {
                if (d[t][ny][nx] <= d[t][p.fst][p.scd] + 1) continue;
                d[t][ny][nx] = d[t][p.fst][p.scd] + 1;
                q.push(pii(ny, nx));
            }
        }
    }
}

signed main()
{
    cin >> W >> H;

    rep(i, H) rep(j, W) d[0][i][j] = d[1][i][j] = inf;

    rep(i, H) rep(j, W) cin >> C[i][j];

    {
        int type = 0;
        rep(i, H) rep(j, W) {
            if (C[i][j] == '.') {
                dfs_fill(type, i, j);
                type++;
            }
        }
    }

    rep(i, H) rep(j, W) {
        if (C[i][j] != '#') {
            bfs_shortest_path(C[i][j] - '0', i, j);
        }
    }

    int mi = inf;

    rep(i, H) rep(j, W) {
        if (C[i][j] == '#') {
            rep(k, 4) rep(l, 4) {
                if (k == l) continue;

                int ny1 = i + dy[k], nx1 = j + dx[k];
                int ny2 = i + dy[l], nx2 = j + dx[l];
                if (!inside(ny1, nx1)) continue;
                if (!inside(ny2, nx2)) continue;

                chmin(mi, d[0][ny1][nx1] + d[1][ny2][nx2] + 1);
            }
        }
    }

    cout << mi << endl;
}