A boy throws a ball into air at \( 45^\circ \) from the horizontal to land it on a roof of a building of height \( H \). If the ball attains maximum height in \( 2 \, \text{s} \) and lands on the building in \( 3 \, \text{s} \) after launch, then value of \( H \) is _______ \( \text{m} \). (\( g = 10 \, \text{m/s}^2 \))