Convert different text user inputs to integers in a while-try loop in python

I´m still new to python and trying to convert a string user input to an integer. My code looks like that:

var_input = input("Please input XX for a or YY for b:")

while True:
    
    try:
        
        if var_input == "XX":
            var_v = 1
            
        elif var_input == "YY":
            var_v = 0
        
        break;
    except ValueError:
        print("Invalid Input")

I´m always ending up with var_v = 0

I´m sure there is a really simple way but i don´t get there.

Thankful for any help!