rdp.py

 """
 E --> nT
 T --> *nT | @

 """

 def non_terminal_E(input_token, lookahead):
 	if input_token == "n":
 		lookahead = match(input_token,"n", lookahead)
 		non_terminal_T(input_token, lookahead)
 	else:
 		error()

 def non_terminal_T(input_token, lookahead):
 	if input_token == "*":
 		lookahead = match(input_token,"*", lookahead)
 		if input_token == "n":
 			lookahead = match(input_token,"n", lookahead)
 			non_terminal_T(input_token, lookahead)
 		else:
 			error()
 	else:
 		error()

def match(input_token, token, lookahead):
	if input_token != token:
		error()
	else:
		lookahead += 1
		return lookahead

def error():
	print "Error. Parsing Failed..."

string = input("Enter the string:")
input_token = list(string)

print "Your input:"input_token

non_terminal_E(input_token, 0)