#define MOD_TYPE 1

#pragma region Macros

#include <bits/stdc++.h>
using namespace std;

#if 0
#include <boost/multiprecision/cpp_int.hpp>
#include <boost/multiprecision/cpp_dec_float.hpp>
using Int = boost::multiprecision::cpp_int;
using lld = boost::multiprecision::cpp_dec_float_100;
#endif
#if 1
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#endif
using ll = long long int;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pld = pair<ld, ld>;
template <typename Q_type>
using smaller_queue = priority_queue<Q_type, vector<Q_type>, greater<Q_type>>;

constexpr ll MOD = (MOD_TYPE == 1 ? (ll)(1e9 + 7) : 998244353);
//constexpr ll MOD = 1;
constexpr int INF = (int)1e9 + 10;
constexpr ll LINF = (ll)4e18;
constexpr double PI = acos(-1.0);
constexpr double EPS = 1e-9;
constexpr int Dx[] = {0, 0, -1, 1, -1, 1, -1, 1, 0};
constexpr int Dy[] = {1, -1, 0, 0, -1, -1, 1, 1, 0};

#define REP(i, m, n) for (ll i = m; i < (ll)(n); ++i)
#define rep(i, n) REP(i, 0, n)
#define REPI(i, m, n) for (int i = m; i < (int)(n); ++i)
#define repi(i, n) REPI(i, 0, n)
#define MP make_pair
#define MT make_tuple
#define YES(n) cout << ((n) ? "YES" : "NO") << "\n"
#define Yes(n) cout << ((n) ? "Yes" : "No") << "\n"
#define possible(n) cout << ((n) ? "possible" : "impossible") << "\n"
#define Possible(n) cout << ((n) ? "Possible" : "Impossible") << "\n"
#define Yay(n) cout << ((n) ? "Yay!" : ":(") << "\n"
#define all(v) v.begin(), v.end()
#define NP(v) next_permutation(all(v))
#define dbg(x) cerr << #x << ":" << x << "\n";

struct io_init
{
  io_init()
  {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << setprecision(30) << setiosflags(ios::fixed);
  };
} io_init;
template <typename T>
inline bool chmin(T &a, T b)
{
  if (a > b)
  {
    a = b;
    return true;
  }
  return false;
}
template <typename T>
inline bool chmax(T &a, T b)
{
  if (a < b)
  {
    a = b;
    return true;
  }
  return false;
}
inline ll CEIL(ll a, ll b)
{
  return (a + b - 1) / b;
}
template <typename A, size_t N, typename T>
inline void Fill(A (&array)[N], const T &val)
{
  fill((T *)array, (T *)(array + N), val);
}
template <typename T, typename U>
constexpr istream &operator>>(istream &is, pair<T, U> &p) noexcept
{
  is >> p.first >> p.second;
  return is;
}
template <typename T, typename U>
constexpr ostream &operator<<(ostream &os, pair<T, U> &p) noexcept
{
  os << p.first << " " << p.second;
  return os;
}
#pragma endregion

#pragma region mint
template <int MOD>
struct Fp
{
  long long val;

  constexpr Fp(long long v = 0) noexcept : val(v % MOD)
  {
    if (val < 0)
      v += MOD;
  }

  constexpr int getmod()
  {
    return MOD;
  }

  constexpr Fp operator-() const noexcept
  {
    return val ? MOD - val : 0;
  }

  constexpr Fp operator+(const Fp &r) const noexcept
  {
    return Fp(*this) += r;
  }

  constexpr Fp operator-(const Fp &r) const noexcept
  {
    return Fp(*this) -= r;
  }

  constexpr Fp operator*(const Fp &r) const noexcept
  {
    return Fp(*this) *= r;
  }

  constexpr Fp operator/(const Fp &r) const noexcept
  {
    return Fp(*this) /= r;
  }

  constexpr Fp &operator+=(const Fp &r) noexcept
  {
    val += r.val;
    if (val >= MOD)
      val -= MOD;
    return *this;
  }

  constexpr Fp &operator-=(const Fp &r) noexcept
  {
    val -= r.val;
    if (val < 0)
      val += MOD;
    return *this;
  }

  constexpr Fp &operator*=(const Fp &r) noexcept
  {
    val = val * r.val % MOD;
    if (val < 0)
      val += MOD;
    return *this;
  }

  constexpr Fp &operator/=(const Fp &r) noexcept
  {
    long long a = r.val, b = MOD, u = 1, v = 0;
    while (b)
    {
      long long t = a / b;
      a -= t * b;
      swap(a, b);
      u -= t * v;
      swap(u, v);
    }
    val = val * u % MOD;
    if (val < 0)
      val += MOD;
    return *this;
  }

  constexpr bool operator==(const Fp &r) const noexcept
  {
    return this->val == r.val;
  }

  constexpr bool operator!=(const Fp &r) const noexcept
  {
    return this->val != r.val;
  }

  friend constexpr ostream &operator<<(ostream &os, const Fp<MOD> &x) noexcept
  {
    return os << x.val;
  }

  friend constexpr istream &operator>>(istream &is, Fp<MOD> &x) noexcept
  {
    return is >> x.val;
  }
};

Fp<MOD> modpow(const Fp<MOD> &a, long long n) noexcept
{
  if (n == 0)
    return 1;
  auto t = modpow(a, n / 2);
  t = t * t;
  if (n & 1)
    t = t * a;
  return t;
}

using mint = Fp<MOD>;
#pragma endregion

template <typename T>
class Matrix
{
public:
  size_t N, M;
  vector<vector<T>> data;

  Matrix(size_t N_, size_t M_) : N(N_), M(M_)
  {
    data.resize(N, vector<T>(M));
  }

  Matrix operator+(const Matrix &A)
  {
    assert(A.N == N && A.M == M);
    Matrix res(N, M);
    rep(i, N) rep(j, M) res[i][j] = data[i][j] + A[i][j];
    return res;
  }

  Matrix &operator+=(const Matrix &A)
  {
    assert(A.N == N && A.M == M);
    rep(i, N) rep(j, M) data[i][j] += A[i][j];
    return *this;
  }

  Matrix operator-(const Matrix &A)
  {
    assert(A.N == N && A.M == M);
    Matrix<T> res(N, M);
    rep(i, N) rep(j, M) res.data[i][j] = data[i][j] - A[i][j];
    return res;
  }

  Matrix &operator-=(const Matrix &A)
  {
    assert(A.N == N && A.M == M);
    rep(i, N) rep(j, M) data[i][j] -= A[i][j];
    return *this;
  }

  Matrix operator*(const Matrix &A)
  {
    assert(M == A.N);
    Matrix res(N, A.M);

    rep(i, N) rep(j, A.M)
    {
      rep(k, M) res[i][j] += data[i][k] * A[k][j];
    }
    return res;
  }

  Matrix &operator*=(const Matrix<T> &A)
  {
    return *this = *this * A;
  }

  Matrix operator*(T a)
  {
    Matrix res(N, M);
    rep(i, N) rep(j, M) res[i][j] = data[i][j] * a;
    return res;
  }

  Matrix &operator*=(ll a)
  {
    rep(i, N) rep(j, M) data[i][j] *= a;
    return *this;
  }

  inline const vector<T> &operator[](int index) const
  {
    return (data.at(index));
  }

  inline vector<T> &operator[](int index)
  {
    return (data.at(index));
  }

  bool operator==(Matrix &A)
  {
    if (N != A.N || M != A.M)
      return false;

    rep(i, N) rep(j, M)
    {
      if (data[i][j] != A[i][j])
        return false;
    }
    return true;
  }

  bool operator!=(Matrix &A)
  {
    return !(*this == A);
  }

  Matrix transpose()
  {
    Matrix res(M, N);
    rep(i, N) rep(j, M) res[j][i] = data[i][j];
    return res;
  }

  T trace()
  {
    assert(N == M);
    T res = 0;
    rep(i, N) res += data[i][i];
    return res;
  }

  void display()
  {
    rep(i, N)
    {
      rep(j, M) cerr << data[i][j] << " ";
      cerr << "\n";
    }
  }

  Matrix E(const int n)
  {
    Matrix res(n, n);
    rep(i, n) rep(j, n) res[i][j] = (i == j);
    return res;
  }

  Matrix pow(ll n)
  {
    assert(N == M);
    Matrix P = *this, res = E(N);
    while (n > 0)
    {
      if (n & 1)
        res *= P;
      P *= P;
      n >>= 1;
    }
    return res;
  }
};

template <typename T>
Matrix<T> operator*(ll a, Matrix<T> &A)
{
  Matrix<T> res(A.N, A.M);
  rep(i, A.N) rep(j, A.M) res[i][j] = A[i][j] * a;
  return res;
}

void solve()
{
  mint a, b;
  ll n;
  cin >> a >> b >> n;
  Matrix<mint> A(2, 1), tran(2, 2);
  A[0][0] = a * 2, A[1][0] = 2;
  tran[0][0] = a * 2, tran[0][1] = -a * a + b;
  tran[1][0] = 1, tran[1][1] = 0;
  tran = tran.pow(n);
  A.display();
  A = tran * A;
  cout << A[1][0] << "\n";
}

int main()
{
  solve();
}