fn distance2(ax: i32, ay: i32, bx: i32, by: i32) -> i32 {
    let dx: i32 = ax - bx
    let dy: i32 = ay - by
    return dx * dx + dy * dy
}

pub fn main(world: World) -> Void raises {
    if distance2(0, 0, 3, 4) == 25 {
        check world.out.write("haversine ok\n")
    }
}