#include <atcoder/all>
#include <bitset>
#include <fstream>
#include <functional>
#include <iostream>
#include <iomanip>
#include <limits>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdio.h>
#include <stdlib.h>
#include <unordered_map>
#include <unordered_set>
#include <vector>
using namespace std;
using namespace atcoder;

typedef long long ll;
typedef long double ld;
typedef std::pair<int, int> pii;
typedef std::pair<int, ll> pil;
typedef std::pair<ll, int> pli;
typedef std::pair<ll, ll> pll;
typedef std::pair<int, ld> pid;
typedef std::pair<int, std::string> pis;
typedef std::pair<ll, std::string> pls;
typedef std::vector<bool> vb;
typedef std::vector<vb> vvb;
typedef std::vector<int> vi;
typedef std::vector<vi> vvi;
typedef std::vector<vvi> vvvi;
typedef std::vector<vvvi> vvvvi;
typedef std::vector<ll> vl;
typedef std::vector<vl> vvl;
typedef std::vector<vvl> vvvl;
typedef std::vector<vvvl> vvvvl;
typedef std::vector<ld> vd;
typedef std::vector<vd> vvd;
typedef std::vector<std::string> vs;
#define rep(i,n) for(auto i=0; i<n; ++i)
#define repm(i,s,n) for(auto i=s; i<n; ++i)
#define repd(i,n) for(auto i=n-1; i>=0; --i)
#define repdm(i,e,n) for(auto i=n-1; i>=e; --i)
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()

template <class T> inline bool chmax(T& a, T b, int eq = 0) { if (a < b || (a == b && eq)) { a = b; return 1; } return 0; }
template <class T> inline bool chmin(T& a, T b, int eq = 0) { if (a > b || (a == b && eq)) { a = b; return 1; } return 0; }

template <class mint, internal::is_modint_t<mint>* = nullptr> constexpr istream& operator>>(istream& is, mint& x) noexcept {long long v = 0; std::cin >> v; x = v; return is;}
template <class mint, internal::is_modint_t<mint>* = nullptr> constexpr ostream& operator<<(ostream& os, const mint& x) noexcept {os << x.val(); return os;}
inline void _n() { std::cout << std::endl; }
template <class T> inline void _(const T a) { std::cout << a; }
template <class T> inline void _l(const T a) { _(a); _n(); }
template <class T> inline void _s(const T a) { _(a); _(' '); }
template <class T> inline void _v(const std::vector<T> v) { for(auto a : v) _(a); }
template <class T> inline void _vl(const std::vector<T> v) { for(auto a : v) _l(a); }
template <class T> inline void _vs(const std::vector<T> v) { for(auto a : v) _s(a); _n(); }
template <class T> inline void _vvl(const std::vector<std::vector<T>> v) { for(auto a : v) { _v(a); _n(); } }
template <class T> inline void _vvs(const std::vector<std::vector<T>> v) { for(auto a : v) { _vs(a); } }
inline void ynl(const bool b) {_l(b ? "yes" : "no");}
inline void yns(const bool b) {_l(b ? "Yes" : "No");}
inline void ynu(const bool b) {_l(b ? "YES" : "NO");}

constexpr int INF = numeric_limits<int>::max() >> 1;
constexpr long long INF_LL = numeric_limits<long long>::max() >> 1LL;
constexpr long long MOD1 = 1000000007;
constexpr long long MOD9 = 998244353;
using mint1 = atcoder::modint1000000007;
using mint9 = atcoder::modint998244353;

//* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ *//

template <class T> struct matrix {

    using vec = std::vector<T>;
    using mat = std::vector<std::vector<T>>;
    mat _matrix;

    matrix() {}
    matrix(int n) : _matrix(n, vec(n, 0)) {}
    matrix(int n, int m) : _matrix(n, vec(m, 0)) {}

    int height() const { return (int)_matrix.size(); }
    int width() const { return (int)_matrix[0].size(); }
    static matrix id(int n) {
        matrix Id(n);
        for(int i = 0; i < n; i++) Id[i][i] = 1;
        return Id;
    }

    inline const vec &operator[](int k) const {
        return (_matrix.at(k));
    }
    inline vec &operator[](int k) {
        return (_matrix.at(k));
    }

    matrix operator+(const matrix &rhs) const {
        return (matrix(*this) += rhs);
    }
    matrix operator-(const matrix &rhs) const {
        return (matrix(*this) -= rhs);
    }
    matrix operator*(const T &rhs) const {
        return (matrix(*this) *= rhs);
    }
    matrix operator*(const matrix &rhs) const {
        return (matrix(*this) *= rhs);
    }

    matrix &operator+= (const matrix &rhs) {
        int n = height(), m = width();
        assert(n == rhs.height() && m == rhs.width());
        for(int i = 0; i < n; i++)
        for(int j = 0; j < m; j++)
        (*this)[i][j] += rhs[i][j];
        return (*this);
    }
    matrix &operator-= (const matrix &rhs) {
        int n = height(), m = width();
        assert(n == rhs.height() && m == rhs.width());
        for(int i = 0; i < n; i++)
        for(int j = 0; j < m; j++)
        (*this)[i][j] -= rhs[i][j];
        return (*this);
    }
    matrix &operator*= (const T &rhs) {
        int n = height(), m = width();
        for(int i = 0; i < n; i++)
        for(int j = 0; j < m; j++)
        (*this)[i][j] *= rhs;
        return (*this);
    }
    matrix &operator*= (const matrix<T> &rhs) {
        int n = height(), m = rhs.width(), l = width();
        assert(l == rhs.height());
        mat R(n, vec(m, 0));
        for(int i = 0; i < n; i++)
        for(int k = 0; k < l; k++)
        for(int j = 0; j < m; j++)
        R[i][j] += (*this)[i][k] * rhs[k][j];
        _matrix.swap(R);
        return (*this);
    }

    matrix &pow_inplace(long long p) {
        assert(height() == width());
        assert(p >= 0);
        matrix R = matrix::id(height());
        while(p > 0) {
            if(p & 1) R *= *this;
            *this *= *this;
            p >>= 1LL;
        }
        _matrix.swap(R._matrix);
        return *this;
    }
    matrix pow(long long p) const { return matrix(*this).pow_inplace(p); }

    vec operate(const vec &v) {
        int n = height(), m = width();
        assert(m == v.size());
        vec r(m, 0);
        for(int i = 0; i < n; i++)
        for(int j = 0; j < m; j++)
        r[i] += (*this)[i][j] * v[j];
        return r;
    }

};

void solve() {
    
    
    
    using mint = atcoder::modint;
    mint::set_mod(10);

    ll p, q, r; cin >> p >> q >> r;
    ll K; cin >> K;

    matrix<mint> M(3);
    M[0][0] = M[0][1] = M[0][2] = M[1][0] = M[2][1] = 1;
    M = M.pow_inplace(K-3);
    vector<mint> av = M.operate({r, q, p});
    mint ans = av[0];
    _l(ans);
    
    
    
    
    
    
    
}

//* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ *//

int main() {
    
    std::ifstream in("input.txt");
    std::cin.rdbuf(in.rdbuf());
    std::cin.tie(0);
    std::cout.tie(0);
    std::ios::sync_with_stdio(false);
    
    solve();
    
    return 0;
}