#include <iostream>

using lint = long long;

template<class T, T MOD>
class Modint{
	T val;
public:
	Modint(T val = 0) : val(val % MOD + (val >= 0 ? 0 : MOD)) {}
	operator T(){ return val; }
	Modint &operator+=(const Modint &a){ val += a.val; if(val >= MOD) val -= MOD; return *this; }
	Modint &operator-=(const Modint &a){ val -= a.val; if(val < 0) val += MOD; return *this; }
	Modint &operator*=(const Modint &a){ val = val * a.val % MOD; return *this; }
	void inverse(){T x[2]={MOD,val},a[2]={0,1};int i;for(i=0;x[!i];i^=1){a[i]-=x[i]/x[!i]*a[!i];x[i]=x[i]%x[!i];}if(!i)a[i]+= MOD;val=a[i];}
	Modint &operator/=(Modint a){ a.inverse(); return *this *= a; }
	friend Modint modpow(Modint a, int n){ Modint ret(1); while(n){ if(n & 1) ret *= a; a *= a; n >>= 1; } return ret; }
	friend Modint operator+(Modint a, const Modint &b){ return a += b; }
	friend Modint operator-(Modint a, const Modint &b){ return a -= b; }
	friend Modint operator*(Modint a, const Modint &b){ return a *= b; }
	friend Modint operator/(Modint a, const Modint &b){ return a /= b; }
	friend std::ostream &operator<<(std::ostream &os, const Modint &a){ return os << a.val; }
};
using Mint = Modint<lint, 1000000007ll>;

template <class T>
struct mat{
	T x00, x01, x10, x11;
	mat(const T &x00, const T &x01, const T &x10, const T &x11): x00(x00), x01(x01), x10(x10), x11(x11) {}
	friend mat operator*(const mat &a, const mat &b){
		return mat(
			a.x00 * b.x00 + a.x01 * b.x10,
			a.x00 * b.x01 + a.x01 * b.x11,
			a.x10 * b.x00 + a.x11 * b.x10,
			a.x10 * b.x01 + a.x11 * b.x11
		);
	}
};

int main(){
	lint a, b, n;
	std::cin >> a >> b >> n;

	if(n == 0){
		std::cout << 2 << std::endl;
		return 0;
	}

	mat<Mint> x(1, 0, 0, 1), y(2 * a, b - a * a, 1, 0);

	--n;
	while(n){
		if(n & 1){
			x = x * y;
		}
		y = y * y;
		n >>= 1;
	}

	std::cout << x.x00 * Mint(a * 2) + x.x01 * Mint(2) << std::endl;
}