What is the time complexity of this while loop with two random operation and one if-else statement?

code is here:

combine_set = set()
total_num = k         # A constant variable
save_idx = 0
while save_idx < total_num:
    main_txt = random.choice(main_text)    # using python random module select a txt from list
    minor_txt = random.choice(minor_text)
    if (main_txt, minor_txt) in combine_set:
        continue
    else:
        save_idx += 1
        combine_set.add((main_txt, minor_txt))
        res = Combiner(main_txt, minor_txt)

I want to figure out the time complexity of this while loop. The Combiner operation's time complexity is O(n), and from here I know the time complexity of random.choice(list) in python is O(logn).

Now, my main problem is that I don't know how to handle the continue statement inside the if statement. Can anyone help me?