int bai1()
{
      int vertices = 0;
      int edge = 0;
      int i, j;
      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]);
                  if (matrix[i][j] == 0)
                        vertices = vertices + 1;
                  }
                  printf("map[%d][%d] = %d\n", i, j, matrix[i][j]);
            }
      for (i = 1; i <= n; i++)
      {
            for (j = 1; j <= n; j++)
            {
                  if(matrix[i][j] == 0)
                  {
                        if(matrix[i][j+1] == 0)
                        edge = edge + 1;
                  }
                  if(matrix[i][j] == 0)
                  {
                        if(matrix[i+1][j] == 0)
                        edge = edge + 1;
                  }
            }
      }
      printf("%d\n", vertices);
      printf("%d\n", edge);
      return 0;
}