search_tree = [
      [
         [[],'B',[]],
      'A',
         [[],'C',[]]
      ],
  'S',
      [
          [
             [[],'F',[]],
          'E',
             [[],'G',[]]
          ],
      'D',
          [
             [[],'I',[]],
          'H',
             [[],'J',[]]
          ]
      ]
  ]

open_list = [search_tree,]
while open_list:
    x = open_list.pop(0)
    print x[1],
    if x[1] == 'G':
        print ' **Goal**',
        break
    if x[0]:
        open_list.append(x[0])
    if x[2]:
        open_list.append(x[2])
print