Please answer a question about the following article about Switzerland:

Direct democracy and federalism are hallmarks of the Swiss political system. Swiss citizens are subject to three legal jurisdictions: the commune, canton and federal levels. The 1848 federal constitution defines a system of direct democracy (sometimes called half-direct or representative direct democracy because it is aided by the more commonplace institutions of a representative democracy). The instruments of this system at the federal level, known as civic rights (Volksrechte, droits civiques), include the right to submit a constitutional initiative and a referendum, both of which may overturn parliamentary decisions.

What two things do citizens have the right to submit to overturn parliamentary decisions?
a constitutional initiative and a referendum