def is_sorted(lst):
    count_digit = dict([(i, 0) for i in lst])
    for i in lst:
        count_digit[i]+=1 
    if any(count_digit[i] > 2 for i in lst):
        return False
    if all(lst[i-1] <= lst[i] for i in range(1, len(lst))):
        return True
    else:
        return False
    
    
from typing import List
def separate_paren_groups(paren_string: str) -> List[str]:
    result = []
    current_string = []
    current_depth = 0
    for c in paren_string:
        if c == '(':
            current_depth += 1
            current_string.append(c)
        elif c == ')':
            current_depth -= 1
            current_string.append(c)
            if current_depth == 0:
                result.append(''.join(current_string))
                current_string.clear()
    return result