Soaked by a water balloon the size of a beach ball, launched by a catapult build by Dwayne, the neighborhood cranky old man, Little Johnny, the neighborhood menace, rolls horizontally off the low part of his house's roof, and into the pile of leaves that his neighbor Mrs. Johnson has just raked up. If Johnny falls for 0.78 seconds, how high was the part of the roof Johnny rolled off? Give your answer to the nearest meter (do not include sign or units).