def solve(s):
    flg = 0
    idx = 0
    new_str = list(s)
    for i in s:
        if i.isalpha():
            new_str[idx] = i.swapcase()
            flg = 1
        idx += 1
    s = ""
    for i in new_str:
        s += i
    if flg == 0:
        return s[len(s)::-1]
    return s
from typing import List
def has_close_elements(numbers: List[float], threshold: float) -> bool:
    for idx, elem in enumerate(numbers):
        for idx2, elem2 in enumerate(numbers):
            if idx != idx2:
                distance = abs(elem - elem2)
                if distance < threshold:
                    return True
    return False