def encrypt(s):
  # this function returns the encrypted form of s

def decrypt(s):
  # this function returns the decrypted form of s

def main():
  #s = "14:00/the ships are in position"
  #s = "21:30/17,25_21,12,25_12,25,21,24,19_14,9_21,14,14,21,23,5"
  while True:
    s = input("\nEnter e plain-text or d coded-text or q: ")
    if s[0] == "e":
      print("Encrypted text is: "+encrypt(s[2:]))
    elif s[0] == "d":
      print("Decrypted text is: "+decrypt(s[2:])) 
    elif s[0] == "q":
      break
    else:
      print("Invalid choice")

main()