#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <tuple>
#include <queue>
#include <deque>
#include <map>
#include <set>
#include <cmath>
#include <iomanip>
#include <cassert>
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) (int)(x).size()
using namespace std;
using ll = long long;
constexpr ll INF = 3000000000000000000;

constexpr int MOD = 1000000007;
struct ModInt {
    ll x;
    ModInt (ll a) : x((a % MOD + MOD) % MOD) {}
    ModInt operator- () const {
        return ModInt(-x);
    }
    ModInt &operator+= (const ModInt &a) {
        if ((x += a.x) >= MOD) x -= MOD;
        return *this;
    }
    ModInt &operator-= (const ModInt &a) {
        if ((x -= a.x) < 0) x += MOD;
        return *this;
    }
    ModInt &operator*= (const ModInt &a) {
        (x *= a.x) %= MOD;
        return *this;
    }
    ModInt operator+ (const ModInt &a) const {
        ModInt res(*this);
        return res += a;
    }
    ModInt operator- (const ModInt &a) const {
        ModInt res(*this);
        return res -= a;
    }
    ModInt operator* (const ModInt &a) const {
        ModInt res(*this);
        return res *= a;
    }
    ModInt pow(ll t) const {
        if (!t) return 1;
        ModInt a = pow(t / 2);
        a *= a;
        if (t & 1) a *= *this;
        return a;
    }
    ModInt inv() const {
        return pow(MOD - 2);
    }
    ModInt &operator/= (const ModInt &a) {
        return (*this) *= a.inv();
    }
    ModInt operator/ (const ModInt &a) const {
        ModInt res(*this);
        return res /= a;
    }
    friend istream &operator>> (istream &is, ModInt &a) {
        is >> a.x;
        return is;
    }
    friend ostream &operator<< (ostream &os, const ModInt &a){
        os << a.x;
        return os;
    }
};

template <typename T>
struct SquareMatrix {
    int L;
    vector<vector<T>> M;
    T e, f;
    SquareMatrix(int n, const T &x, const T &y) : L(n), M(n, vector<T>(n, x)), e(x), f(y) {}
    const vector<T> &operator[](int k) const {
        return M[k];
    }
    vector<T> &operator[](int k) {
        return M[k];
    }
    SquareMatrix &operator+=(const SquareMatrix &x) {
        REP(i, L) REP(j, L) (*this)[i][j] += x[i][j];
        return (*this);
    }
    SquareMatrix &operator-=(const SquareMatrix &x) {
        REP(i, L) REP(j, L) (*this)[i][j] -= x[i][j];
        return (*this);
    }
    SquareMatrix &operator*=(const SquareMatrix &x) {
        SquareMatrix res(L, e, f);
        REP(i, L) REP(j, L) REP(k, L) res[i][j] += ((*this)[i][k] * x[k][j]);
        swap((*this).M, res.M);
        return (*this);
    }
    SquareMatrix &operator^=(ll n) {
        SquareMatrix res(L, e, f);
        REP(i, L) res[i][i] = f;
        while (n) {
            if (n & 1) res *= (*this);
            (*this) *= (*this);
            n >>= 1;
        }
        swap((*this).M, res.M);
        return (*this);
    }
    SquareMatrix operator+(const SquareMatrix &x) const {
        return SquareMatrix(*this) += x;
    }
    SquareMatrix operator-(const SquareMatrix &x) const {
        return SquareMatrix(*this) -= x;
    }
    SquareMatrix operator*(const SquareMatrix &x) const {
        return SquareMatrix(*this) *= x;
    }
    SquareMatrix operator^(ll n) const {
        return SquareMatrix(*this) ^= n;
    }
};

int main() {
    int a, b, n;
    cin >> a >> b >> n;
    SquareMatrix<ModInt> M(2, ModInt(0), ModInt(1));
    M[0][0] = ModInt(a);
    M[0][1] = ModInt(b);
    M[1][0] = ModInt(1);
    M[1][1] = ModInt(0);
    M ^= n;
    cout << M[1][0] << "\n";
    return 0;
}