FLAMES using string slicing (Python)

flames.py

# Copied from https://github.com/TheZoom110/fun-projects/blob/main/flames.py

def flames(name1: str, name2: str) -> str:
    # Convert strings to a standard format
    a = list(name1.upper())
    b = list(name2.upper())
    # While iterating over a,
    # Removing i'th element from it will cause the i+1'th element to take its place
    # In next iteration, i+2'th element, now in i+1'th index, will be be operated against
    # Thus, i+1'th element will be skipped
    # To avoid that, create a temporary copy of a to iterate over
    for i in list(a):
        if i in b:
            a.remove(i)
            b.remove(i)
    n = len(a) + len(b)

    f = "FLAMES"
    f_len = 6

    while f_len > 1:
        r = n % f_len
        if r == 0:
            # Remove last element
            f = f[: f_len - 1]
            f_len -= 1
        else:
            # Remove r-1'th letter; start from r'th letter next
            f = f[r:] + f[: r - 1]
            f_len -= 1

    return f[0]