Histogram of the number of LMC (upper panels) and SMC (lower panels) Cepheids, including F and 1O, as a function of fundamentalized pulsating period. The colored points show the expected number of Cepheids in each bin for different IS crossings, calculated using Eq. (1). The sum of the expected numbers of stars for all IS crossings is shown as a black solid line. The vertical blue, red, and green lines mark pulsation periods of 0.6 (the shortest period of our LMC models), 3, and 2.5 days, respectively.