#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include <sys/types.h>
#include <time.h>

int main(int argc, char*argv[]){
  int K = atoi(argv[1]);
  char* board = new char[K*K];
  time_t result = time(NULL);
  unsigned int seed = result;

  srand(seed);
  int i;
  for(i = 0; i< K*K; i++)
    board[i] = '_';
  for(i=0; i < K/2; i++){
    //X's move
    int move;
    do{
      move = (int) rint(rand() * 1.0 /RAND_MAX * (K*K - 1));
    }
    while (board[move]!='_');
    board[move] = 'X';
    //O's move
    do{
      move = (int) rint(rand() * 1.0 /RAND_MAX * (K*K - 1));
    }
    while (board[move]!='_');
    board[move] = 'O';     
  }
  FILE* f = fopen("b.txt","wt");
  for (i=0; i<K*K; i++)
    fprintf(f,"%c", board[i]);
  fclose(f);
  delete []board;
}