#[allow(unused_imports)]
use std::io::{stdout, BufWriter, Write};

fn main() {
    let out = stdout();
    let mut out = BufWriter::new(out.lock());
    inputv! {
        t:usize
    }
    for _ in 0..t {
        let mut s = input_line_str()
            .to_charvec()
            .iter()
            .map(|&q| q.to_string().parse::<usize>().unwrap())
            .collect::<Vec<_>>();
        while s.len() != 1 {
            let mut v = vec![];
            for i in 0..s.len() - 1 {
                let i1 = s[i].to_string().parse::<usize>().unwrap();
                let i2 = s[i + 1].to_string().parse::<usize>().unwrap();
                let q = if i1 + i2 >= 10 {
                    1 + (i1 + i2) % 10
                } else {
                    i1 + i2
                };
                v.push(q);
            }
            s = v;
            //dbg!(&s);
        }
        writeln!(out, "{}", s[0]).unwrap();
    }
}
//https://github.com/manta1130/competitive-template-rs

pub mod input {
    use std::cell::RefCell;
    use std::io;
    pub const SPLIT_DELIMITER: char = ' ';
    pub use std::io::prelude::*;

    #[macro_export]
    thread_local! {
        pub static INPUT_BUFFER:RefCell<std::collections::VecDeque<String>>=RefCell::new(std::collections::VecDeque::new());
    }

    #[macro_export]
    macro_rules! inputv {
    ( $($x:ident : $t:ty),*) => {
                $(
                INPUT_BUFFER.with(|p| if p.borrow().len()==0{
                    let temp_str = input_line_str();
                    let mut split_result_iter = temp_str.split(SPLIT_DELIMITER).map(|q|q.to_string()).collect::<std::collections::VecDeque<_>>();
                    p.borrow_mut().append(&mut split_result_iter)
                });
                let mut buf_split_result=String::new();
                INPUT_BUFFER.with(|p| buf_split_result = p.borrow_mut().pop_front().unwrap());
                    let $x:$t = buf_split_result.parse().unwrap();
                )*
    };
}

    #[macro_export]
    macro_rules! input_all {
    ( $($x:ident : $t:ty),*) => {
                $(
                INPUT_BUFFER.with(|p| if p.borrow().len()==0{
                    let mut temp_str = String::new();
                    std::io::stdin().read_to_string(&mut temp_str).unwrap();
                    let mut split_result_iter = temp_str.split_whitespace().map(|q|q.to_string()).collect::<std::collections::VecDeque<_>>();
                    p.borrow_mut().append(&mut split_result_iter)
                });
                let mut buf_split_result=String::new();
                INPUT_BUFFER.with(|p| buf_split_result = p.borrow_mut().pop_front().unwrap());
                    let ($x):($t) = buf_split_result.parse().unwrap();
                )*
    };
}

    pub fn input_line_str() -> String {
        let mut s = String::new();
        io::stdin().read_line(&mut s).unwrap();
        s.trim().to_string()
    }

    #[allow(clippy::match_wild_err_arm)]
    pub fn input_vector<T>() -> Vec<T>
    where
        T: std::str::FromStr,
    {
        let mut v: Vec<T> = Vec::new();

        let s = input_line_str();
        let split_result = s.split(SPLIT_DELIMITER);
        for z in split_result {
            let buf = match z.parse() {
                Ok(r) => r,
                Err(_) => panic!("Parse Error",),
            };
            v.push(buf);
        }
        v
    }

    #[allow(clippy::match_wild_err_arm)]
    pub fn input_vector_row<T>(n: usize) -> Vec<T>
    where
        T: std::str::FromStr,
    {
        let mut v = Vec::with_capacity(n);
        for _ in 0..n {
            let buf = match input_line_str().parse() {
                Ok(r) => r,
                Err(_) => panic!("Parse Error",),
            };
            v.push(buf);
        }
        v
    }

    pub trait ToCharVec {
        fn to_charvec(&self) -> Vec<char>;
    }

    impl ToCharVec for String {
        fn to_charvec(&self) -> Vec<char> {
            self.to_string().chars().collect::<Vec<_>>()
        }
    }
}
use input::*;