#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <tuple>
#include <cmath>
#include <numeric>
#include <functional>
#include <cassert>

#define debug_value(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << #x << "=" << x << endl;
#define debug(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << x << endl;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

using namespace std;
typedef long long ll;

const ll MOD = 1000000007;

class ModInt{
    public:
    ll v;
    ModInt(ll _v = 0){
        if(_v >= MOD) _v %= MOD;
        v = _v;
    }
    ModInt operator+(ll n){
        return ModInt((v+n)%MOD);
    }
    ModInt operator-(ll n){
        return ModInt((v-n+MOD)%MOD);
    }
    ModInt operator*(ll n){
        if(n >= MOD) n %= MOD;
        return ModInt((v*n)%MOD);
    }
    ModInt operator/(ll n){
        return ModInt((ModInt(n).inv()*v).v%MOD);
    }

    void operator+=(ll n){
        v = (v+n)%MOD;
    }
    void operator-=(ll n){
        v = (v-n+MOD)%MOD;
    }
    void operator*=(ll n){
        v = (v*n+MOD)%MOD;
    }
    
    
    ModInt operator+(ModInt n){
        return ModInt((v+n.v)%MOD);
    }
    ModInt operator-(ModInt n){
        return ModInt((v-n.v+MOD)%MOD);
    }
    ModInt operator*(ModInt n){
        return ModInt((v*n.v)%MOD);
    }
    ModInt operator/(ModInt n){
        return ModInt((n.inv()*v).v%MOD);
    }

    void operator+=(ModInt n){
        v = (v+n.v)%MOD;
    }
    void operator-=(ModInt n){
        v = (v-n.v+MOD)%MOD;
    }
    void operator*=(ModInt n){
        v = (v*n.v)%MOD;
    }

    void operator=(ModInt n){
        v = n.v;
    }
    bool operator==(ModInt n){
        return v == n.v;
    }
    bool operator!=(ModInt n){
        return v != n.v;
    }
    void operator=(ll n){
        v = n%MOD;
    }

    ModInt inv(){
        if(v == 1) return ModInt(1);
        else return ModInt(MOD-ModInt(MOD%v).inv().v*(MOD/v)%MOD);
    }
};

ostream& operator<<(ostream& os, const ModInt& m){
    os << m.v;
    return os;
}

istream & operator >> (istream &in,  ModInt &m){
    in >> m.v;
    return in;
}

template <typename T>
struct matrix{
    int n, m;
    vector<vector<T>> dat;
    matrix(int n_, int m_){
        n = n_; m = m_;
        for(int i = 0; i < n; i++){
            dat.push_back(vector<T>(m));
        }
    }
    vector<T>& operator[](int x) {
        return dat[x];
	}
};

template <typename T>
bool prod(matrix<T> a, matrix<T> b, matrix<T> &ans){
    assert(a.m == b.n);
    for(int i = 0; i < a.n; i++){
        for(int j = 0; j < b.m; j++){
            ans.dat[i][j] = 0;
            for(int k = 0; k < b.n; k++){
                ans.dat[i][j] += (a.dat[i][k]*b.dat[k][j]);
            }
        }
    }
    return true;
}

template <typename T>
void copy_mat(matrix<T> a, matrix<T> &b){
    assert(a.n == b.n);
    assert(a.m == b.m);
    for(int i = 0; i < a.n; i++){
        for(int j = 0; j < a.m; j++){
            b.dat[i][j] = a.dat[i][j];
        }
    }
}

template <typename T>
void pow_mat(matrix<T> a, ll n, matrix<T> &ans){
    assert(n < ((ll)1<<61));
    matrix<T> buf(a.n, a.n);
    matrix<T> tmp(a.n, a.n);
    copy_mat(a, tmp);

    for(int i = 0; i < a.n; i++) {
        for(int j = 0; j < a.n; j++){
            ans.dat[i][j] = 0;
        }
        ans.dat[i][i] = 1;
    }
    
    for(int i = 0; i <= 60; i++){
        ll m = (ll)1 << i;
        if(m&n){
            prod(tmp, ans, buf);
            copy_mat(buf, ans);
        }
        prod(tmp, tmp, buf);
        copy_mat(buf, tmp);
    }
}

template <typename T>
void print_mat(matrix<T> a){
    for(int i = 0; i < a.n; i++){
        for(int j = 0; j < a.m; j++){
            cout << a.dat[i][j] << ' ';
        }
        cout << endl;
    }
}

template <typename T>
ostream& operator<<(ostream& os, const matrix<T>& m){
    print_mat<T>(m);
    return os;
}

using mint = ModInt;


int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(10) << fixed;
    ll a, b, n; cin >> a >> b >> n;
    ll s = 2*a, t = a*a-b;
    matrix<mint> m(2, 2), p(2, 2), u(2, 1), ans(2, 1);
    m[0][0] = s, m[0][1] = mint(MOD-t);
    m[1][0] = 1;
    u[0][0] = 2*a;
    u[1][0] = 2;
    pow_mat(m, n, p);
    prod(p, u, ans);
    cout << ans[1][0] << endl;
}