// ---------- begin input macro ----------
// reference: https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, bytes) => {
        read_value!($iter, String).bytes().collect::<Vec<u8>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}
// ---------- end input macro ----------

use std::io::Write;
use std::collections::*;

type Map<K, V> = BTreeMap<K, V>;
type Set<T> = BTreeSet<T>;
type Deque<T> = VecDeque<T>;

fn run() {
    input! {
        p: u32,
        q: u32,
        r: u32,
        k: usize,
    }
    let m = 10;
    let p = p % 10;
    let q = q % 10;
    let r = r % 10;
    type Mat = [[u32; 3]; 3];
    let mul = |a: &Mat, b: &Mat| -> Mat {
        let mut c = Mat::default();
        for (c, a) in c.iter_mut().zip(a) {
            for (a, b) in a.iter().zip(b) {
                for (c, b) in c.iter_mut().zip(b) {
                    *c = (*c + *a * *b) % m;
                }
            }
        }
        c
    };
    let mut t = Mat::default();
    for i in 0..3 {
        t[i][i] = 1;
    }
    let mut s = [[1, 1, 1], [1, 0, 0], [0, 1, 0]];
    let mut k = k - 3;
    while k > 0 {
        if k & 1 == 1 {
            t = mul(&t, &s);
        }
        s = mul(&s, &s);
        k >>= 1;
    }
    let ans = r * t[0][0] + q * t[0][1] + p * t[0][2];
    println!("{}", ans % m);
}

fn main() {
    run();
}