def plural(n: int, thing: str) ->str:
    """Add "s" to string if needed.

    >>> plural(0, 'hat'), plural(1, 'hat'), plural(2, 'hat')
    ('0 hats', '1 hat', '2 hats')
    """
    if n == 1:
        return '1 ' + thing
    return f'{n} {thing}s'
