BEGIN_PROGRAM = {
    1   :lambda: goto(2) if response == "yes" else goto(3) if response == "no" else goto 100,
    2   :lambda: print("Thanks for the yes!") or goto(20),
    3   :lambda: print("Thanks for the no!") or goto(20),
    20  :lambda: end(),
    100 :lambda: print("You're annoying me - answer the question!") or goto(1)
}

# pay no attention to the code below the curtain

def goto(linenum):
    global line
    line = linenum

def end():
    goto(0)

line = 1
while line:
    BEGIN_PROGRAM[line]()