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

template<const unsigned int MOD> struct prime_modint {
    using mint = prime_modint;
    unsigned int v;
    prime_modint() : v(0) {}
    prime_modint(int a) { a %= (int)(MOD); if(a < 0)a += MOD; v = a; }
    prime_modint(long long a) { a %= (int)(MOD); if(a < 0)a += MOD; v = a; }
    static constexpr int mod() { return MOD; }
    mint& operator++() {v++; if(v == MOD)v = 0; return *this;}
    mint& operator--() {if(v == 0)v = MOD; v--; return *this;}
    mint operator++(int) { mint result = *this; ++*this; return result; }
    mint operator--(int) { mint result = *this; --*this; return result; }
    mint& operator+=(const mint& rhs) { v += rhs.v; if(v >= MOD) v -= MOD; return *this; }
    mint& operator-=(const mint& rhs) { if(v < rhs.v) v += MOD; v -= rhs.v; return *this; }
    mint& operator*=(const mint& rhs) {
        v = (unsigned int)((unsigned long long)(v) * rhs.v % MOD);
        return *this;
    }
    mint& operator/=(const mint& rhs) { return *this = *this * rhs.inv(); }
    mint operator+() const { return *this; }
    mint operator-() const { return mint() - *this; }
    mint pow(long long n) const {
        assert(0 <= n);
        mint r = 1, x = *this;
        while (n) {
            if (n & 1) r *= x;
            x *= x;
            n >>= 1;
        }
        return r;
    }
    mint inv() const { assert(v); return pow(MOD - 2); }
    friend mint operator+(const mint& lhs, const mint& rhs) { return mint(lhs) += rhs; }
    friend mint operator-(const mint& lhs, const mint& rhs) { return mint(lhs) -= rhs; }
    friend mint operator*(const mint& lhs, const mint& rhs) { return mint(lhs) *= rhs; }
    friend mint operator/(const mint& lhs, const mint& rhs) { return mint(lhs) /= rhs; }
    friend bool operator==(const mint& lhs, const mint& rhs) { return (lhs.v == rhs.v); }
    friend bool operator!=(const mint& lhs, const mint& rhs) { return (lhs.v != rhs.v); }
    friend std::ostream& operator << (std::ostream &os, const mint& rhs) noexcept { return os << rhs.v; }
};
using mint = prime_modint<1000000007>;
//using mint = prime_modint<998244353>;

template <class T, size_t N> struct Matrix {
    std::array<std::array<T, N>, N> A{};
    Matrix() {}
    Matrix(const std::array<std::array<T, N>, N> &M) : A(M){}
    Matrix(const std::vector<std::vector<T>> &M)  {
        for(size_t i = 0; i < N; i++){
            for(size_t j = 0; j < N; j++){
                A[i][j] = M[i][j];
            }
        }
    }
    const std::array<T, N>& operator[](int i) const { return A[i]; }
    std::array<T, N>& operator[](int i) { return A[i]; }

    Matrix& operator+=(const Matrix& rhs) {
        for(size_t i = 0; i < N; i++){
            for(size_t j = 0; j < N; j++){
                A[i][j] += rhs[i][j];
            }
        }
        return *this;
    }
    Matrix& operator-=(const Matrix& rhs) {
        for(size_t i = 0; i < N; i++){
            for(size_t j = 0; j < N; j++){
                A[i][j] -= rhs[i][j];
            }
        }
        return *this;
    }
    Matrix& operator*=(const Matrix& rhs) {
        std::array<std::array<T, N>, N> res{};
        for(size_t i = 0; i < N; i++){
            for(size_t j = 0; j < N; j++){
                for(size_t k = 0; k < N; k++){
                    res[i][j] += A[i][k] * rhs[k][j];
                }
            }
        }
        swap(A, res);
        return *this;
    }
    Matrix& operator+() const { return *this; }
    Matrix& operator-() const { return Matrix() - *this; }
    friend Matrix operator+(const Matrix& lhs, const Matrix& rhs) {
        return Matrix(lhs) += rhs;
    }
    friend Matrix operator-(const Matrix& lhs, const Matrix& rhs) {
        return Matrix(lhs) -= rhs;
    }
    friend Matrix operator*(const Matrix& lhs, const Matrix& rhs) {
        return Matrix(lhs) *= rhs;
    }
    friend bool operator==(const Matrix& lhs, const Matrix& rhs) {
        return (lhs.A == rhs.A);
    }
    friend bool operator!=(const Matrix& lhs, const Matrix& rhs) {
        return (lhs.A != rhs.A);
    }
    Matrix pow(long long v){
        Matrix res, temp = A;
        for(size_t i = 0; i < N; i++)res[i][i] = 1;
        while(v){
            if(v & 1)res *= temp;
            temp *= temp;
            v >>= 1;
        }
        return res;
    }
    friend std::ostream& operator << (std::ostream &os, const Matrix& rhs) noexcept {
        for(size_t i = 0; i < N; i++){
            if(i) os << '\n';
            for(size_t j = 0; j < N; j++){
                os << (j ? " " : "") << rhs[i][j];
            }
        }
        return os;
    }
};

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int a, b, n;
    cin >> a >> b >> n;
    if(n == 0){
        cout << 0 << '\n';
        return 0;
    }
    Matrix<mint, 2> Mt({{a, 1}, {b, 0}});
    Mt = Mt.pow(n - 1);
    cout << Mt[0][0] << '\n';
}