Notes

def state_q0(i):
global state
if i == "a" or i == "b":
state = "q1"

def state_q1(i):
global state
if i == "a" or i == "b":
state = "q2"

def state_q2(i):
global state
if i == "a" or i == "b":
state = "q2"
else:
state = "q0"

def dfa(input_str):
global state
state = "q0"


if input_str == "":
print("Invalid input: empty string.")
return

if input_str[0] != 'a' and input_str[0] != 'b':
print("Invalid input: invalid starting character.")
return


for i in input_str:
if state == "q0":
state_q0(i)
elif state == "q1":
state_q1(i)
elif state == "q2":
state_q2(i)


if state == "q2":
print("Accepted")
else:
print("Rejected")


input_str = input("Enter input string containing 'a' and 'b' of length 2: ")


if len(input_str) == 2:
dfa(input_str)
else:
print("Invalid input: The string must have exactly 2 characters.")