#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using ll = long long;
using namespace std;
using namespace __gnu_pbds;
template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const double pi = acos(-1);
const int N = 12 + 1, K = 80 + 1, SQ = 500, M = 1e9 + 7;
//#define TESTS
//#define INTERACTIVE
//#define COMMUNICATION
/*
* Remember who you are.
*/
void pre() {
}
string c[2 * N], ans[2 * N];
int dp[N][K][1 << N][2], vis[N][K][1 << N][2], n, m, vid;
int rec(int i, int j, int mask, bool up) {
if (i == n / 2)
return up ? (int) 1e9 : rec(0, j + 1, mask, 0);
if (j == m / 2)
return 0;
auto &ret = dp[i][j][mask][up];
auto &v = vis[i][j][mask][up];
if (v == vid)
return ret;
ret = 1e9;
v = vid;
char cur = c[2 * i + 1][2 * j + 1];
char bot = c[2 * i + 2][2 * j + 1];
char right = c[2 * i + 1][2 * j + 2];
if (cur == 'X') {
if (up && (~mask >> i & 1))
ret = min(ret, rec(i + 1, j, mask, false) + 1);
else if (!up) {
if (mask >> i & 1)
ret = min(ret, rec(i + 1, j, mask ^ (1 << i), false) + 1);
else {
if (bot == ' ')
ret = min(ret, rec(i + 1, j, mask, true) + 1);
if (right == ' ')
ret = min(ret, rec(i + 1, j, mask | (1 << i), false) + 1);
}
}
} else {
if (up) {
if (mask >> i & 1)
ret = min(ret, rec(i + 1, j, mask ^ (1 << i), false) + 2);
else {
if (bot == ' ')
ret = min(ret, rec(i + 1, j, mask, true) + 2);
if (right == ' ')
ret = min(ret, rec(i + 1, j, mask | (1 << i), false) + 2);
}
} else {
if (mask >> i & 1) {
if (bot == ' ')
ret = min(ret, rec(i + 1, j, mask ^ (1 << i), true) + 2);
if (right == ' ')
ret = min(ret, rec(i + 1, j, mask, false) + 2);
} else {
ret = min(ret, rec(i + 1, j, mask, false));
if (bot == ' ' && right == ' ')
ret = min(ret, rec(i + 1, j, mask | (1 << i), true) + 2);
}
}
}
return ret;
}
void build(int i, int j, int mask, bool up) {
if (i == n / 2) {
return build(0, j + 1, mask, 0);
}
if (j == m / 2)
return;
char cur = c[2 * i + 1][2 * j + 1];
char bot = c[2 * i + 2][2 * j + 1];
char right = c[2 * i + 1][2 * j + 2];
int best = rec(i, j, mask, up);
if (cur == 'X') {
if (up && (~mask >> i & 1)) {
if (rec(i + 1, j, mask, false) + 1 == best) {
build(i + 1, j, mask, false);
ans[2 * i][2 * j + 1] = '.';
return;
}
} else if (!up) {
if (mask >> i & 1) {
if (rec(i + 1, j, mask ^ (1 << i), false) + 1 == best) {
build(i + 1, j, mask ^ (1 << i), false);
ans[2 * i + 1][2 * j] = '.';
return;
}
} else {
if (bot == ' ') {
if (rec(i + 1, j, mask, true) + 1 == best) {
build(i + 1, j, mask, true);
ans[2 * i + 2][2 * j + 1] = '.';
return;
}
}
if (right == ' ') {
if (rec(i + 1, j, mask | (1 << i), false) + 1 == best) {
build(i + 1, j, mask | (1 << i), false);
ans[2 * i + 1][2 * j + 2] = '.';
return;
}
}
}
}
} else {
if (up) {
if (mask >> i & 1) {
if (rec(i + 1, j, mask ^ (1 << i), false) + 2 == best) {
build(i + 1, j, mask ^ (1 << i), false);
ans[2 * i + 1][2 * j] = '.';
ans[2 * i][2 * j + 1] = '.';
ans[2 * i + 1][2 * j + 1] = '.';
return;
}
} else {
if (bot == ' ') {
if (rec(i + 1, j, mask, true) + 2 == best) {
build(i + 1, j, mask, true);
ans[2 * i][2 * j + 1] = '.';
ans[2 * i + 1][2 * j + 1] = '.';
ans[2 * i + 2][2 * j + 1] = '.';
return;
}
}
if (right == ' ') {
if (rec(i + 1, j, mask | (1 << i), false) + 2 == best) {
build(i + 1, j, mask | (1 << i), false);
ans[2 * i][2 * j + 1] = '.';
ans[2 * i + 1][2 * j + 1] = '.';
ans[2 * i + 1][2 * j + 2] = '.';
return;
}
}
}
} else {
if (mask >> i & 1) {
if (bot == ' ') {
if (rec(i + 1, j, mask ^ (1 << i), true) + 2 == best) {
build(i + 1, j, mask ^ (1 << i), true);
ans[2 * i + 1][2 * j] = '.';
ans[2 * i + 1][2 * j + 1] = '.';
ans[2 * i + 2][2 * j + 1] = '.';
return;
}
}
if (right == ' ') {
if (rec(i + 1, j, mask, false) + 2 == best) {
build(i + 1, j, mask, false);
ans[2 * i + 1][2 * j] = '.';
ans[2 * i + 1][2 * j + 1] = '.';
ans[2 * i + 1][2 * j + 2] = '.';
return;
}
}
} else {
if (rec(i + 1, j, mask, false) == best) {
build(i + 1, j, mask, false);
return;
}
if (bot == ' ' && right == ' ')
if (rec(i + 1, j, mask | (1 << i), true) + 2 == best) {
build(i + 1, j, mask | (1 << i), true);
ans[2 * i + 1][2 * j + 1] = '.';
ans[2 * i + 2][2 * j + 1] = '.';
ans[2 * i + 1][2 * j + 2] = '.';
return;
}
}
}
}
}
void solve() {
cin >> n >> m;
cin.ignore();
for (int i = 0; i < n; ++i)
getline(cin, c[i]), ans[i] = c[i];
++vid;
cout << rec(0, 0, 0, false) << '\n';
build(0, 0, 0, 0);
for (auto &i: ans)
cout << i << '\n';
}
void solve2() {
}
signed main() {
ios::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
#ifdef CAROOT
#ifndef INTERACTIVE
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
#else
#endif
int tt = 1;
pre();
#ifdef COMMUNICATION
string run;
cin >> run;
#endif
#ifdef TESTS
cin >> tt;
#endif
for (int tc = 1; tc <= tt; ++tc) {
#ifdef COMMUNICATION
if (run == "first")
solve();
else
solve2();
#else
solve();
#endif
cout << '\n';
}
}
