??????

fn digital_root(n: i64) -> i64 {
    println!("{}", n);
    let sum = n.to_string().into_bytes();
    if n.to_string().len() == 2 {
        let x1 = (sum[0]-48) as i64;
        let x2 = (sum[1]-48) as i64;
        return x1+x2;
    }
    else{
        let mut x:i64 = 0;
        for i in 0..n.to_string().len() {
            x += (sum[i] - 48) as i64;
        }
        return digital_root(x);
    }
}

fn main(){
    let x = digital_root(132186738569);
    println!("{}", x);
}