#include <bits/stdc++.h>

using namespace std;

const long long int MOD = 1e9 + 7;
vector <vector<long long int>> mul(vector <vector<long long int>> a, vector<vector<long long int>> b)
{
	vector <vector<long long int>>c(2, vector<long long int>(2));
	c[0][0] = 0;
	c[0][1] = 0;
	c[1][0] = 0;
	c[1][1] = 0;

	for (int i = 0; i < 2; i++)
	{
		for (int j = 0; j < 2; j++)
		{
			for (int k = 0; k < 2; k++)
			{
				c[i][j] += (a[i][k] * b[k][j]);
				c[i][j] %= MOD;
			}
		}
	}

	return c;
}

int main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);

	vector <vector <long long int>> a(2, vector<long long int>(2));
	vector <vector <long long int>> b(2, vector<long long int>(2));
	long long int n, A, B;

	cin >> A >> B >> n;
	a[0][0] = A;
	a[0][1] = B;
	a[1][0] = 1;
	a[1][1] = 0;

	b[0][0] = 1;
	b[0][1] = 0;
	b[1][0] = 0;
	b[1][1] = 1;

	while (n > 0)
	{
		if (n & 1)
		{
			b = mul(a, b);
		}
		a = mul(a, a);
		n >>= 1;
	}

	cout << b[1][0] << '\n';

    return 0;
}