#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using mint = modint1000000007;
const int mod = 1000000007;
//using mint = modint998244353;
//const int mod = 998244353;
//const int INF = 1e9;
//const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n-1); i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define endl "\n"
#define P pair<int,int>
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
vector<vector<mint>> mul(vector<vector<mint>>&A, vector<vector<mint>>&B) {
	vector<vector<mint>> C(A.size(), vector<mint>(B[0].size()));
	rep(i, A.size()) rep(j, B[0].size()) rep(k, A[0].size()) C[i][j] += A[i][k] * B[k][j];
	return C;
}
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int a, b, n; cin >> a >> b >> n;
	if (0 == n) {
		cout << 0 << endl;
		return 0;
	}
	n--;
	vector<vector<mint>> mans(2, vector<mint>(2));
	rep(i, 2)mans[i][i] = 1;
	vector<vector<mint>> mpow(2, vector<mint>(2));
	mpow[0][0] = a, mpow[0][1] = b;
	mpow[1][0] = 1, mpow[1][1] = 0;
	while (n > 0) {
		if (1 == n % 2) mans = mul(mpow, mans);
		mpow = mul(mpow, mpow);
		n /= 2;
	}
	cout << mans[0][0].val() << endl;
	return 0;
}