#include <atcoder/all>
#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
using namespace atcoder;
using namespace std;
using ll = long long;
using ull = unsigned long long;
using mll = static_modint<998244353>;
#define rep(i,n) for(int i=0; i<(n); i++)

template<class Elem, size_t matrix_sz>
struct static_matrix {
  Elem X[matrix_sz][matrix_sz] = {};
  static static_matrix id() { static_matrix res; rep(i, matrix_sz) res[i][i] = 1; return res; }
  Elem* operator[](int x) { return X[x]; }
  const Elem* operator[](int x) const { return X[x]; }
  static_matrix operator+(const static_matrix& r) const {
    static_matrix res;
    rep(i, matrix_sz) rep(j, matrix_sz)
      res[i][j] = X[i][j] + r[i][j];
    return res;
  }
  static_matrix operator-(const static_matrix& r) const {
    static_matrix res;
    rep(i, matrix_sz) rep(j, matrix_sz)
      res[i][j] = X[i][j] - r[i][j];
    return res;
  }
  static_matrix operator*(const static_matrix& r) const {
    static_matrix res;
    rep(i, matrix_sz) rep(j, matrix_sz) rep(k, matrix_sz)
      res[i][j] += X[i][k] * r[k][j];
    return res;
  }
  static_matrix pow(ll N) const {
    if (N == 0) return id();
    static_matrix res = pow(N / 2);
    res = res * res;
    if (N % 2 == 1) res = res * *this;
    return res;
  }
};

using Mat = static_matrix<static_modint<10>,3>;

int main(){
  ll p,q,r,k; cin >> p >> q >> r >> k;
  k -= 3;
  Mat G;
  G[1][0] = 1;
  G[2][1] = 1;
  G[0][2] = 1;
  G[1][2] = 1;
  G[2][2] = 1;
  G = G.pow(k);
  auto ans = (G[0][2] * p + G[1][2] * q + G[2][2] * r).val();
  cout << ans << endl;
  return 0;
}

struct ios_do_not_sync{
  ios_do_not_sync(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
  }
} ios_do_not_sync_inst;