#include <string>
#include <vector>
#include <list>
#include <cmath>
#include <algorithm>
#include <map>
#include <set>
#include <iostream>
#include <cstdio>
#include <cstdlib>
using namespace std;

int main()
{
  int r, c, q, o, no, i, j, rr, rc;
  vector <string> b;

  srand(time(0));

  r = rand()%50+1;
  c = rand()%50+1;
  q = rand()%20;
  o = rand()%1000;
  no = 0;

  b.resize(r);
  for (i = 0; i < b.size(); i++) b[i].resize(c, '.');
  for (i = 0; i < q; i++) {
    rr = rand()%r;
    rc = rand()%c;
    b[rr][rc] = '?';
  }
  for (i = 0; i < b.size(); i++) {
    for (j = 0; j < b[0].size(); j++) {
      if (b[i][j] != '?' && rand()%1000 <= o) {
        no++;
        b[i][j] = 'O';
      }
    }
  }

  if (no == 0) b[rand()%r][rand()%c] = 'O';

  for (i = 0; i < b.size(); i++) printf("%s\n", b[i].c_str());
  exit(0);
}