#include <bits/stdc++.h>
#include <cstdio>
#include <ext/pb_ds/assoc_container.hpp>
#define FAST_IO ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);cerr.tie(0)
#define pb push_back
#define all(x) begin(x), end(x)
#define umap unordered_map
#define space " "
#define TEST_CASES int a; cin >> a; for (int i = 0; i < a; i++) {solve(); cout << endl;}
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count());
class HashedString {
private:
// change M and B if you want
static const ll M = (1LL << 61) - 1;
static const ll B;
// pow[i] contains B^i % M
static vector<ll> pow;
// p_hash[i] is the hash of the first i characters of the given string
vector<ll> p_hash;
__int128 mul(ll a, ll b) { return (__int128)a * b; }
ll mod_mul(ll a, ll b) { return mul(a, b) % M; }
public:
HashedString(const string &s) : p_hash(s.size() + 1) {
while (pow.size() < s.size()) { pow.push_back(mod_mul(pow.back(), B)); }
p_hash[0] = 0;
for (int i = 0; i < s.size(); i++) {
p_hash[i + 1] = (mul(p_hash[i], B) + s[i]) % M;
}
}
ll get_hash(int start, int end) {
ll raw_val = p_hash[end + 1] - mod_mul(p_hash[start], pow[end - start + 1]);
return (raw_val + M) % M;
}
};
vector<ll> HashedString::pow = {1};
const ll HashedString::B = uniform_int_distribution<ll>(0, M - 1)(rng);
void solve() {
int b, c; cin >> b >> c;
vector<string> vec(2 * b);
vector<HashedString> hashes;
for (int i = 0; i < b; i++) {
cin >> vec[i];
vec[i] += vec[i];
vec[i + b] += vec[i];
hashes.pb(HashedString(vec[i]));
}
for (int i = 0; i < b; i++) {
hashes.pb(HashedString(vec[i]));
}
pair<int, int> res = {b - 1, c - 1};
vector<int> start(2 * c, b - 1);
for (int i = b - 1; i < 2 * b; i++) {
for (int j = c - 1; j < 2 * c; j++) {
if (i < start[j]) {
continue;
}
for (int k = b - 1; k >= 0; k--) {
if (hashes[res.first - k].get_hash(res.second - c + 1, res.second) !=
hashes[i - k].get_hash(j - c + 1, j)) {
int lo = 0; int hi = c - 1;
while (lo < hi) {
int mid = (lo + hi) / 2;
if (hashes[res.first - k].get_hash(res.second - c + 1, res.second - c + 1 + mid) !=
hashes[i - k].get_hash(j - c + 1, j - c + 1 + mid)) {
hi = mid;
}
else {
lo = mid + 1;
}
}
if (vec[res.first - k][res.second - c + 1 + hi] == '*') {
for (int l = 0; l <= hi; l++) {
start[j -c + 1 + l] = max(start[j - c + 1 + l], i + b - k);
}
}
else {
res = {i, j};
}
break;
}
}
}
}
for (int i = res.first - b + 1; i <= res.first; i++) {
for (int j = res.second - c + 1; j <= res.second; j++) {
cout << vec[i][j];
}
cout << endl;
}
}
int main() {
FAST_IO;
//freopen("lightsout.in", "r", stdin);
//freopen("lightsout.out", "w", stdout);
//TEST_CASES;
solve(); cout << endl;
/*int a; cin >> a;
for (int i = 1; i <= a; i++){
cout << "Case #" << i << ": ";
solve();
cout << endl;
}*/
}
