fn bottlesLeft(start: u32, verses: u32) -> u32 {
    var value: u32 = start
    var i: u32 = 0
    while i < verses {
        if value > 0 {
            value = value - 1
        }
        i = i + 1
    }
    return value
}

pub fn main(world: World) -> Void raises {
    if bottlesLeft(99, 3) == 96 {
        check world.out.write("bottles ok\n")
    }
}