def find_smallest(num_vars):
    """Find the smallest exponent of two that is greater than the number
    of variables

    Parameters
    ----------
    num_vars : int
        Number of variables

    Returns
    -------
    x : int
        Smallest exponent of two greater than `num_vars`
    """
    for x in range(10):
        if num_vars <= 2 ** x:
            return x