int bai2()
{
      int gate = 0;
      int i,j;
      int x,y;
      FILE *f;
      f = fopen("data1.txt", "r");
      if (f == NULL)
      {
            printf("ERROR\n");
      }
      else
      {
            fscanf(f, "%d", &n);
      }
      for (i = 1; i <= n; i++)
      {
            for (j = 1; j <= n; j++)
            {
                  fscanf(f, "%d", &matrix[i][j]);
                  printf("map[%d][%d] = %d\n", i, j, matrix[i][j]);
            }
      }
            for(y=1; y<=n; y++){
                  if(matrix[1][1] == 0)
                  gate = gate + 0.5;
                  if(matrix[1][6] == 0)
                  gate = gate + 0.5;
                  if(matrix[1][y] == 0)
                  gate = gate +1;
                  if(matrix[6][y] == 0)
                  gate = gate +1;
            }
            for(x=1; x<=n; x++){
                  if(matrix[1][1] == 0)
                  gate = gate + 0.5;
                  if(matrix[6][1] == 0)
                  gate = gate + 0.5;
                  if(matrix[x][1] == 0)
                  gate = gate +1;
                  if(matrix[x][6] == 0)
                  gate = gate +1;
            }
      printf("%d\n", gate);
      return 0;
}