Meggy brought a flute to a campfire. The flute is made of the ABS polymer with thermal expansion coefficient α = 9·10⁻⁵ K⁻¹. When she tried playing it indoors at 20°C, its lowest tone had frequency 349 Hz and the flute had length l. Near the fire, she placed the flute on a bench. Assuming that the period of sound waves forming each tone is proportional to the length of the flute, determine the frequency of its lowest tone, if the flute got heated up to 25°C in the meantime. Meggy was creating problems during a Fykos camp.