Output repeating four times - python-3.x

Question

I'm new to python. I'm trying to make a project that orders and sets up combo meals. The problem is that when printing our the receipt, the receipt prints out four times. May I ask for help on how to fix this? I have tried rearranging the code, and trying multiple if statements but none have seem to work.
cart=[]
mains_total=[]
sides_total=[]
drinks_total=[]
sides=[]
drinks=[]
everything_total=[]
stuff={"steak": int(900), "salmon": int(850), "chicken": int(300)}
stuff2={"baked potato": int(80), "mashed potato": int(75), "steamed vegetables": int(50)}
stuff3={"ice tea": int(55), "root beer": int(60), "water": int(20)}
def system():
print("Thanks for using our service, please select an option.\n(1) mains\n(2) sides\n(3) drinks\n(4)
check-out\n(5) exit")
print("Please order one of each category.")
customer_input=int(input("Please type your answer here:"))
if customer_input==1:
print("steak=900")
print("salmon=850")
print("chicken=300")
global mains_order
mains_order=input("What would you like to order?:")
cart.append(mains_order)
system()
if customer_input==2:
print("baked potato=80")
print("mashed potato=75")
print("steamed vegetables=50")
global sides_order
sides_order=input("What would you like to order?:")
sides.append(sides_order)
system()
if customer_input==3:
print("ice tea=55")
print("root beer=60")
print("water=20")
global drinks_order
drinks_order=input("What would you like to order?:")
drinks.append(drinks_order)
system()
if customer_input==4:
for items in cart:
mains_total.append(stuff[items])
global total_sum
total_sum=sum(mains_total)
for items in sides:
sides_total.append(stuff2[items])
global total_sides
total_sides=sum(sides_total)
for items in drinks:
drinks_total.append(stuff3[items])
global total_drinks
total_drinks=sum(drinks_total)
print(cart, total_sum)
print(sides, total_sides)
print(drinks, total_drinks)
everything_total.append(total_sum)
everything_total.append(total_sides)
everything_total.append(total_drinks)
global total_everything
global total_everything
total_everything=(sum(everything_total))
print(total_everything)
global price_input
price_input=int(input("How much would you like to pay?:"))
if '300' '75' '55' in everything_total:
discounted_price=total_everything/100*10
print("this is your discounted price:", discounted_price)
if price_input<total_everything:
print("Sorry you have insuficient funds. Please restate your order and try agian.")
else:
print(cart, total_sum)
print(sides, total_sides)
print(drinks, total_drinks)
print("price total", total_everything)
print("price paid", price_input)
system()