System.py

print("----------------------- ATM machine ---------------------------")
PIN = "0111"
while True :
    print("1-Check balance")
    print("2-Deposit money")
    print("3-Withdrwan money")
    print("4-Exit")
    pin = int(input("Enter pin "))
    if pin == PIN :
        choice = int(input("Enter choice  : "))
        if choice == 1 :
            balance = 0
            print("Your current balance  :",balance)
        if choice == 2 :
            deposit = float(input("Enter Deposit amount : "))
            balance += deposit
            print("you have deposit : ",deposit)
            print("Your current balance  :",balance)
        if choice == 3 :
            withdrawn = float(input("Enter Withdrawn amount : "))
        if withdrawn <=balance :
            balance -= withdrawn
            print("you have withdrawn : ",withdrawn)
            print("Your current balance  :",balance)
        else :
            print("Insufficient balance .") 
        if choice == 4 :
            exit(0)
    else :
        print("Invalid Pin")