def interpret(block: str):
    """
    Interprets an element block, breaking it into element and number of that element.

    :param block: string block describing an element
    :return: composition dictionary
    :rtype: dict
    """
    if block[0].isdigit() is True:  # if isotope number is encountered
        return {block: 1}
    else:
        ele = block[0]
        i = 0
        num = ''
        while i < len(block) - 1:
            i += 1
            if block[i].isdigit() is True:  # add digits
                num += block[i]
            else:
                ele += block[i]
        if num == '':
            num = 1
        else:
            num = int(num)
        return {ele: num}