If-statement issue [duplicate]

i just started with python i tried to make 2 loops first loop to be sure that the client enter the right entry the other loop to resolve the calculation variables and all the time i get "Unknown Entry"

OperationSelected = False UnKnownEntry = False

while OperationSelected == False or UnKnownEntry == True: try: operation = input("Select operation to perform:\r\n1>PLUS\r\n2>MINU\r\n3>MULTIP\r\n4>DIVIDE\r\n>>> ")

    if operation != "1" or operation != "2" or operation != "3" or operation != "4":
        print("--------------------------")
        print("Unknown entry. ( " + operation + " )")
        print("--------------------------")
        UnKnownEntry == True
    else: 
        print("TEST")
        OperationSelected = True
        UnKnownEntry = False

except Exception as e:
    print(e)
    break

while OperationSelected == True and UnKnownEntry == False: try:
num1 = input("Enter first number: ") num2 = input("Enter second number: ")

    if operation == "1":
        print("--------------------------------------")
        print("The Sulotion is: " + str(float(num1) + float(num2)))
        print("--------------------------------------")
    elif operation == "2":
            print("--------------------------------------")
            print("The Sulotion is: " + str(float(num1) - float(num2)))
            print("--------------------------------------")
    elif operation == "3":
        print("--------------------------------------")
        print("The Sulotion is: " + str(float(num1) * float(num2)))
        print("--------------------------------------")
    elif operation == "4":
        print("--------------------------------------")
        print("The Sulotion is: " + str(float(num1) / float(num2)))
        print("--------------------------------------")
except Exception as e:
    print(e)








    break