#include <iostream>
#include <vector>
#include <cassert>
using std::cout;
using std::endl;
using std::vector;
using std::pair;
constexpr char CRATER = '*';
constexpr char EMPTY = '.';
constexpr int MOD = 1e9 + 7;
long long pow(long long base, long long exp, long long mod) {
assert(exp >= 0);
base %= exp;
long long res = 1;
while (exp > 0) {
if (exp % 2 == 1) {
res = (res * base) % mod;
}
base = base * base % mod;
exp /= 2;
}
return res;
}
long long mod_inv(long long n, long long mod) { return pow(n, mod - 2, mod); }
/**
* https://evaluator.hsin.hr/tasks/HONI202135sateliti/
* (sample input omitted due to length)
*/
int main() {
int row_num;
int col_num;
std::cin >> row_num >> col_num;
vector<long long> pow2((row_num * 2) * (col_num * 2));
vector<long long> pow2_mod_invs(pow2.size());
pow2[0] = pow2_mod_invs[0] = 1;
long long base_inv = mod_inv(2, MOD);
for (int p = 1; p < pow2.size(); p++) {
pow2[p] = pow2[p - 1] * 2 % MOD;
pow2_mod_invs[p] = (pow2_mod_invs[p - 1] * base_inv) % MOD;
}
vector<vector<bool>> times2(row_num * 2, vector<bool>(col_num * 2));
for (int r = 0; r < row_num; r++) {
for (int c = 0; c < col_num; c++) {
char cell;
std::cin >> cell;
times2[r][c] = times2[r + row_num][c + col_num] = cell != CRATER;
times2[r + row_num][c] = times2[r][c + col_num] = cell != CRATER;
}
}
vector<vector<long long>> pref_vals(
times2.size() + 1, vector<long long>(times2[0].size() + 1)
);
for (int r = 0; r < times2.size(); r++) {
for (int c = 0; c < times2[r].size(); c++) {
// don't think overflow would happen
pref_vals[r + 1][c + 1] = (
pref_vals[r + 1][c]
+ pref_vals[r][c + 1]
- pref_vals[r][c]
+ times2[r][c] * pow2[r * (2 * col_num) + c]
);
}
}
auto sum_rect = [&] (int sr, int sc, int er, int ec) {
return (
pref_vals[er + 1][ec + 1] + pref_vals[sr][sc]
- pref_vals[sr][ec + 1] - pref_vals[er + 1][sc]
);
};
auto hash = [&] (int r, int c, int square_num) {
int row_amt = square_num / col_num;
long long total = 0;
if (row_amt > 0) {
total += sum_rect(r, c, r + row_amt - 1, c + col_num - 1);
}
if (square_num % col_num > 0) {
int rem = square_num % col_num;
total += sum_rect(r + row_amt, c, r + row_amt, c + rem - 1);
}
return total % MOD * pow2_mod_invs[r * (2 * col_num) + c] % MOD;
};
pair<int, int> best{0, 0};
for (int sr = 0; sr < row_num; sr++) {
for (int sc = 0; sc < col_num; sc++) {
if (sr == 0 && sc == 0) {
continue;
}
int lo = 0;
int hi = row_num * col_num;
int eq_chars = -1;
while (lo <= hi) {
int mid = (lo + hi) / 2;
long long best_hash = hash(best.first, best.second, mid);
long long this_hash = hash(sr, sc, mid);
if (best_hash == this_hash) {
eq_chars = mid;
lo = mid + 1;
} else {
hi = mid - 1;
}
}
int dr = eq_chars / col_num;
int dc = eq_chars % col_num;
if (times2[sr + dr][sc + dc] < times2[best.first + dr][best.second + dc]) {
best = {sr, sc};
}
}
}
for (int r = 0; r < row_num; r++) {
for (int c = 0; c < col_num; c++) {
cout << (times2[best.first + r][best.second + c] ? EMPTY : CRATER);
}
cout << '\n';
}
}
