#include <bits/stdc++.h>

using namespace std;

#define REP(i, n) for (int i=0; i<(n); ++i)
#define RREP(i, n) for (int i=(int)(n)-1; i>=0; --i)
#define FOR(i, a, n) for (int i=(a); i<(n); ++i)
#define RFOR(i, a, n) for (int i=(int)(n)-1; i>=(a); --i)

#define SZ(x) ((int)(x).size())
#define ALL(x) (x).begin(),(x).end()

#define DUMP(x) cerr<<#x<<" = "<<(x)<<endl
#define DEBUG(x) cerr<<#x<<" = "<<(x)<<" (L"<<__LINE__<<")"<<endl;

template<class T>
ostream &operator<<(ostream &os, const vector<T> &v) {
  os << "[";
  REP(i, SZ(v)) {
    if (i) os << ", ";
    os << v[i];
  }
  return os << "]";
}

template<class T, class U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
  return os << "(" << p.first << " " << p.second << ")";
}

template<class T>
bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}

template<class T>
bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return true;
  }
  return false;
}

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using P = pair<int, int>;
using vi = vector<int>;
using vll = vector<ll>;
using vvi = vector<vi>;
using vvll = vector<vll>;

const ll MOD = 1e9 + 7;
const int INF = INT_MAX / 2;
const ll LINF = LLONG_MAX / 2;
const ld eps = 1e-9;

template<int m>
struct mint {
  int x;
  mint(ll x = 0) : x(((x % m) + m) % m) {}
  mint operator-() const { return x ? m-x : 0; }
  mint &operator+=(mint r) {
    if ((x += r.x) >= m) x -= m;
    return *this;
  }
  mint &operator-=(mint r) {
    if ((x -= r.x) < 0) x += m;
    return *this;
  }
  mint &operator*=(mint r) {
    x = ((ll)x * r.x) % m;
    return *this;
  }
  mint inv() const { return pow(m-2); }
  mint &operator/=(mint r) { return *this *= r.inv(); }

  friend mint operator+(mint l, mint r) { return l += r; }
  friend mint operator-(mint l, mint r) { return l -= r; }
  friend mint operator*(mint l, mint r) { return l *= r; }
  friend mint operator/(mint l, mint r) { return l /= r; }
  mint pow(ll n) const {
    mint ret = 1, tmp = *this;
    while (n) {
      if (n & 1) ret *= tmp;
      tmp *= tmp, n >>= 1;
    }
    return ret;
  }
  friend bool operator==(mint l, mint r) { return l.x == r.x; }
  friend bool operator!=(mint l, mint r) { return l.x != r.x; }
  friend ostream &operator<<(ostream &os, mint a) {
    return os << a.x;
  }
  friend istream &operator>>(istream &is, mint& a) {
    ll x; is >> x; a = x; return is;
  }
};


/**
 * @brief
 * 行列累乗
 * @author habara-k
 * @date 2020/04/24
 * @param[in] a 行列
 * @param[in] k 指数
 * @return 行列 a^k
 *
 * @details
 * T に渡すのは環であり、operator *, += を定義すること
 */

template<class T>
using Matrix = vector<vector<T>>;

template<class T>
Matrix<T> operator*(const Matrix<T>& A, const Matrix<T>& B) {
  assert(A[0].size() == B.size());
  int n = A.size(), m = B[0].size(), p = A[0].size();
  Matrix<T> C(n, vector<T>(m));
  for (int i = 0; i < n; ++i)
    for (int j = 0; j < m; ++j)
      for (int k = 0; k < p; ++k)
        C[i][j] += A[i][k] * B[k][j];
  return C;
}

template<class T>
Matrix<T> po(Matrix<T> a, ll k) {
  assert(a.size() == a[0].size());
  int n = a.size();
  Matrix<T> ret(n, vector<T>(n));
  for (int i = 0; i < n; ++i) ret[i][i] = 1;
  while (k) {
    if (k & 1) ret = ret * a;
    a = a * a; k >>= 1;
  }
  return ret;
}

ll powm(ll a, ll n, ll m) {
  ll ret = 1;
  while (n > 0) {
    if (n & 1) (ret *= a) %= m;
    (a *= a) %= m;
    n >>= 1;
  }
  return ret;
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(10);

  using Int = mint<MOD>;

  Int a, b;
  ll n;
  cin >> a >> b >> n;

  Matrix<Int> A(2, vector<Int>(2, 0));
  A[0][0] = a;
  A[0][1] = (b - a * a) * Int(4).inv();
  A[1][0] = 1;

  auto B = po(A, n);
  cout << (a * B[1][0] + 2 * B[1][1]) * Int(2).pow(n) << endl;

  return 0;
}