SyntaxError: can’t assign to operator. python script with potentiometer

Python Help
1

Hallo!
Script stops with this error:
pin-a = 18
^
SyntaxError: can’t assign to operator

What do I need to change to make it work?

´´´
import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)

pin-a = 18
pin-b = 24

def discharge():
GPIO.setup(pin-a, GPIO.IN)
GPIO.setup(pin-b, GPIO.OUT)
GPIO.output(pin-b, False)
time.sleep(0.004)

def charge_time():
GPIO.setup(pin-b, GPIO.IN)
GPIO.setup(pin-a, GPIO.OUT)
count = 0
GPIO.output(pin-a, True)
while not GPIO.input(b_pin):
count = count + 1
return count

def analog_read():
discharge()
return charge_time()

while True:
print(analog_read())
time.sleep(1)
´´´

2

Dashes/hyphens are not allowed as part of a variable name. Python sees the dash and assumes you mean subtraction. Replace the dashes with underscores if you mean it to be a variable name.