fn thue(n0: u32) -> Bool {
    var n: u32 = n0
    var ones: u32 = 0
    while n > 0 {
        if n % 2 == 1 {
            ones = ones + 1
        }
        n = n / 2
    }
    return ones % 2 == 1
}

pub fn main(world: World) -> Void raises {
    if !thue(6) && thue(7) {
        check world.out.write("thue morse ok\n")
    }
}