def strip_balanced_edge_parens(s):
    """
    Return a string where a pair of balanced leading and trailing parenthesis is
    stripped.

    For instance:
    >>> strip_balanced_edge_parens('(This is a super string)')
    'This is a super string'
    >>> strip_balanced_edge_parens('(This is a super string')
    '(This is a super string'
    >>> strip_balanced_edge_parens('This is a super string)')
    'This is a super string)'
    >>> strip_balanced_edge_parens('(This is a super (string')
    '(This is a super (string'
    >>> strip_balanced_edge_parens('(This is a super (string)')
    '(This is a super (string)'
    """
    if s.startswith('(') and s.endswith(')'):
        c = s[1:-1]
        if '(' not in c and ')' not in c:
            return c
    return s