#include<stdio.h>
#define N 8
int col[N] = { 0 };
int right[2 * N - 1] = { 0 };
int left[2 * N - 1] = { 0 };
int Q[N];
int cnt = 0;
void Print()
{
  int i;
  for (i = 0; i < N; i++)
  {
    for (int j = 0; j < N; j++)
    {
      if (Q[i] == j)
        printf("■");
      else
        printf("□");
    }
    printf("\n");
  }
  printf("==========================\n");
  cnt++;
}
void Queen(int i)
{
  int j;
  for (j = 0; j < N; j++)
  {
    if ((!col[j]) && (!left[i + j]) && (!right[7 + i - j]))
    {
      Q[i] = j;//放皇后
      col[j] = 1;
      left[i + j] = 1;
      right[N - 1 + i - j] = 1;//已有皇后的標(biāo)記
      if (i < N - 1)
      {
        Queen(i + 1);
      }
      else
      {
        Print();
      }
      col[j] = 0;
      right[N - 1 + i - j] = 0;
      left[i + j] = 0;//清除標(biāo)記，查找下一組解
    }
  }
}
int main(void)
{
  Queen(0);
  printf("%d", cnt);
  getchar();
  return 0;
}