In an amusement park maze with all the walls covered with mirrors, Pilar sees Hernando's reflection from a series of three mirrors. If the reflected angle from Mirror 3 is α = 51° for the mirror arrangement shown in the figure, what is the angle of incidence θ on Mirror 1 if this mirror is tilted by angle γ = 15° with respect to other mirrors? (Give your answer in decimal with zero digit after the decimal point, using "degree" (degree°) as unit.)