data = {
 "天津":{
  "南开区":{
   "南开大学":{
    "历史系":{},
    "文学系":{},
    "英语系":{},
   },
   "科技大学":{
    "计算机系":{},
    "机器系":{},
    "软件系":{},
   },
   "理工大学":{
    "数学系":{},
    "化学系":{},
    "物理系":{},
   },
  },
  "武清区":{
   "武清大学":{
    "历史系":{},
    "文学系":{},
    "英语系":{},
   },
   "武清科技大学":{
    "计算机系":{},
    "机器系":{},
    "软件系":{},
   },
   "武清理工大学":{
    "数学系":{},
    "化学系":{},
    "物理系":{},
   },
  },
  "北辰区":{
   "北辰大学":{
    "历史系":{},
    "文学系":{},
    "英语系":{},
   },
   "北辰科技大学":{
    "计算机系":{},
    "机器系":{},
    "软件系":{},
   },
   "北辰理工大学":{
    "数学系":{},
    "化学系":{},
    "物理系":{},
   },
  },
 },
 "河北":{
  "保定市": {
   "保定大学": {
    "历史系": {},
    "文学系": {},
    "英语系": {},
   },
   "保定科技大学": {
    "计算机系": {},
    "机器系": {},
    "软件系": {},
   },
   "保定理工大学": {
    "数学系": {},
    "化学系": {},
    "物理系": {},
   },
  },
  "秦皇岛": {
   "秦皇岛大学": {
    "历史系": {},
    "文学系": {},
    "英语系": {},
   },
   "秦皇岛科技大学": {
    "计算机系": {},
    "机器系": {},
    "软件系": {},
   },
   "秦皇岛理工大学": {
    "数学系": {},
    "化学系": {},
    "物理系": {},
   },
  },
  "石家庄": {
   "石家庄大学": {
    "历史系": {},
    "文学系": {},
    "英语系": {},
   },
   "石家庄科技大学": {
    "计算机系": {},
    "机器系": {},
    "软件系": {},
   },
   "石家庄理工大学": {
    "数学系": {},
    "化学系": {},
    "物理系": {},
   },
  },
 },
 "河南":{
  "郑州市": {
   "郑州大学": {
    "历史系": {},
    "文学系": {},
    "英语系": {},
   },
   "郑州科技大学": {
    "计算机系": {},
    "机器系": {},
    "软件系": {},
   },
   "郑州理工大学": {
    "数学系": {},
    "化学系": {},
    "物理系": {},
   },
  },
  "南阳市": {
   "南阳大学": {
    "历史系": {},
    "文学系": {},
    "英语系": {},
   },
   "南阳科技大学": {
    "计算机系": {},
    "机器系": {},
    "软件系": {},
   },
   "南阳理工大学": {
    "数学系": {},
    "化学系": {},
    "物理系": {},
   },
  },
  "登封市": {
   "登封大学": {
    "历史系": {},
    "文学系": {},
    "英语系": {},
   },
   "登封科技大学": {
    "计算机系": {},
    "机器系": {},
    "软件系": {},
   },
   "登封理工大学": {
    "数学系": {},
    "化学系": {},
    "物理系": {},
   },
  },
 },
}
#exit_flag = False
while True:
 for i in data :
  print (i)
 choice = input ("input:")
 if choice in data:
  while True:
   for i2 in data[choice]:
    print (i2)
   choice2 = input("input2:")
   if choice2 in data[choice]:
    while True:
     for i3 in data[choice][choice2]:
      print (i3)
     choice3 = input("input3:")
     if choice3 in data[choice][choice2]:
      for i4 in data[choice][choice2][choice3]:
       print(i4)
      choice4 = input("Press b to return to the previous level:")
      if choice4 == "b":
       pass
      elif choice4 == "q":
       exit ()
     if choice3 == "b":
      break
     elif choice3 == "q":
      exit()
   if choice2 == "b":
    break
   elif choice2 == "q":
    exit()