text: 
  Dictionary And List
  Description
  You will be converting a dictionary, of string(keys) and list of string (values),  to a list of strings. Please check the sample input/output for clarification.
  
  
  Input:
  A dictionary with keys as strings and values as a list of strings.
  
  Output:
  A list of strings
  
  
  Sample input:
  {‘Mobile’: [‘Redmi’, ‘Samsung’, ‘Realme’], 
  ‘Laptop’: [‘Dell’, ‘HP’],
  ‘TV’: [‘Videocon’, ‘Sony’] }
  
  Sample output:
  [‘Mobile_Redmi’, ‘Mobile_Samsung’, ‘Mobile_Realme’, ‘Laptop_Dell’, ‘Laptop_HP’, ‘TV_Videocon’, ‘TV_Sony’]
  
  
  Sample input:
  { 'Pen': ['Gel', 'Ink', 'ball'],
  'Mobile': ['Android', 'apple'] }
  
  Sample output:
  ['Pen_Gel', 'Pen_Ink', 'Pen_ball', 'Mobile_Android', 'Mobile_apple']
  
  
  
  #input has been taken for you
  import ast
  input_str = input()
  #input dictionary has been received in input_dict
  d= ast.literal_eval(input_str)
  l=[]
  for key in d.keys():
      for w in d[key]:
          l.append(key+'_'+w)
  
  #start writing your code here
  
  print(l)
  
  