N = int(input())

Speed_limit_car_count = 0

all_speed = 0

car_speed = []

i = 0

total = None

YN = None

def list_check(car_speed):

for i in range(len(car_speed)):

 if car_speed[i] in range(1, 300):

  normal = True

  continue

 else:

  normal = False

  break

return normal

if N not in range(1, 31):

print('Wrong input')

else:

while i < N:

 car_speed.append(float(input()))

 i += 1

normal = list_check(car_speed)

if normal:

 for i in range(len(car_speed)):

  if car_speed[i] <= 30:

   Speed_limit_car_count += 1

 for i in range(len(car_speed)):

  round(car_speed[i])

  all_speed += car_speed[i]

 total = all_speed/N

 if Speed_limit_car_count >= 2:

  YN = 'YES'

 else:

  YN = 'NO'

else:

 print('ERROR IN SPEEDLIST. CHEK INPUT!')

print(total, YN)

Программа протестирована. ctrl+c делать не стоит, сайт нарушает табуляции в коде.