pub fn powmod(x: u64, p: u64, m: u64) -> u64 {
    let mut res = x;
    for _ in 1..p {
        res = (res * x) % m;
    }
    return res;
}

pub fn to_bytes(x: u64) -> (u8, u8, u8, u8) {
    return (
        ((x >> 0) & 0xFF) as u8,
        ((x >> 8) & 0xFF) as u8,
        ((x >> 16) & 0xFF) as u8,
        ((x >> 24) & 0xFF) as u8,
    );
}

pub fn from_bytes(x1: u8, x2: u8, x3: u8, x4: u8) -> u64 {
    return (x1 as u64) << 0 | (x2 as u64) << 8 | (x3 as u64) << 16 | (x4 as u64) << 24;
}