#include <bits/stdc++.h>
template <typename T>
void MACRO_VAR_Scan(T& t) {
  std::cin >> t;
}
template <typename First, typename... Rest>
void MACRO_VAR_Scan(First& first, Rest&... rest) {
  std::cin >> first;
  MACRO_VAR_Scan(rest...);
}
template <typename T>
void MACRO_VEC_ROW_Init(int n, T& t) {
  t.resize(n);
}
template <typename First, typename... Rest>
void MACRO_VEC_ROW_Init(int n, First& first, Rest&... rest) {
  first.resize(n);
  MACRO_VEC_ROW_Init(n, rest...);
}
template <typename T>
void MACRO_VEC_ROW_Scan(int p, T& t) {
  std::cin >> t[p];
}
template <typename First, typename... Rest>
void MACRO_VEC_ROW_Scan(int p, First& first, Rest&... rest) {
  std::cin >> first[p];
  MACRO_VEC_ROW_Scan(p, rest...);
}
template <typename T>
void MACRO_OUT(const T t) {
  std::cout << t;
}
template <typename First, typename... Rest>
void MACRO_OUT(const First first, const Rest... rest) {
  std::cout << first << " ";
  MACRO_OUT(rest...);
}
template <class T>
inline T CHMAX(T& a, const T b) {
  return a = (a < b) ? b : a;
}
template <class T>
inline T CHMIN(T& a, const T b) {
  return a = (a > b) ? b : a;
}
template <class T>
using V = std::vector<T>;
template <class T>
using VV = V<V<T>>;
template <typename S, typename T>
std::ostream& operator<<(std::ostream& os, std::pair<S, T> p) {
  os << "(" << p.first << ", " << p.second << ")";
  return os;
}
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using PAIR = std::pair<ll, ll>;
using PAIRLL = std::pair<ll, ll>;
constexpr ll INFINT = (1 << 30) - 1;
constexpr ll INFINT_LIM = (1LL << 31) - 1;
constexpr ll INFLL = 1LL << 60;
constexpr ll INFLL_LIM = (1LL << 62) - 1 + (1LL << 62);
constexpr double EPS = 1e-10;
constexpr ll MOD = 1000000007;
constexpr double PI = 3.141592653589793238462643383279;
template <class T, size_t N>
void FILL(T (&a)[N], const T& val) {
  for (auto& x : a) x = val;
}
template <class ARY, size_t N, size_t M, class T>
void FILL(ARY (&a)[N][M], const T& val) {
  for (auto& b : a) FILL(b, val);
}
template <class T>
void FILL(std::vector<T>& a, const T& val) {
  for (auto& x : a) x = val;
}
template <class ARY, class T>
void FILL(std::vector<std::vector<ARY>>& a, const T& val) {
  for (auto& b : a) FILL(b, val);
}
ll dy8[] = {-1, -1, -1, 0, 1, 1, 1, 0};
ll dx8[] = {-1, 0, 1, 1, 1, 0, -1, -1};
signed main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);
  ;
  ll n, m;
  MACRO_VAR_Scan(n, m);
  ;
  n += 2;
  m += 2;
  VV<char> a(n, V<char>(m, '.'));
  for (ll i = (1); i < (n - 1); ++i)
    for (ll j = (1); j < (m - 1); ++j) std::cin >> a[i][j];
  ll mi = INFINT;
  for (ll _ = 0; _ < ll(2); ++_) {
    VV<ll> b(n, V<ll>(m, 0));
    for (ll i = 0; i < ll(n); ++i) {
      b[i][0] = a[i][0] == 'X';
      for (ll j = (1); j < (m); ++j) {
        if (a[i][j] == 'X') {
          b[i][j] = b[i][j - 1] + 1;
        } else {
          b[i][j] = 0;
        }
      }
      for (ll j = ll(m - 1) - 1; j >= 0; --j) {
        if (a[i][j] == 'X') CHMAX(b[i][j], b[i][j + 1]);
      }
    }
    for (ll i = 0; i < ll(n); ++i)
      for (ll j = 0; j < ll(m); ++j)
        if (b[i][j]) CHMIN(mi, b[i][j]);
    VV<char> c(m, V<char>(n));
    for (ll i = 0; i < ll(n); ++i)
      for (ll j = 0; j < ll(m); ++j) c[j][i] = a[i][j];
    a = c;
    std::swap(n, m);
  }
  ll T = (mi - 1) / 2;
  ll sz = T * 2 + 1;
  VV<ll> dist(n, V<ll>(m, INFINT));
  std::queue<PAIR> que;
  for (ll i = 0; i < ll(n); ++i)
    for (ll j = 0; j < ll(m); ++j) {
      if (a[i][j] == '.') {
        dist[i][j] = 0;
        que.emplace(i, j);
      }
    }
  while (!que.empty()) {
    PAIR now = que.front();
    que.pop();
    for (ll d = 0; d < ll(8); ++d) {
      ll dy = now.first + dy8[d];
      ll dx = now.second + dx8[d];
      if (!(0 <= dy && dy < n) || !(0 <= dx && dx < m)) continue;
      ll t = dist[now.first][now.second] + 1;
      if (dist[dy][dx] > t) {
        dist[dy][dx] = t;
        que.emplace(dy, dx);
      }
    }
  }
  MACRO_OUT(T);
  std::cout << "\n";
  ;
  for (ll i = (1); i < (n - 1); ++i) {
    for (ll j = (1); j < (m - 1); ++j) {
      MACRO_OUT(dist[i][j] >= T + 1 ? 'X' : '.');
      ;
    }
    std::cout << "\n";
    ;
  }
  return 0;
}
