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

class matrix {
  public:
    long x11, x12, x21, x22;
};

matrix mul(matrix, matrix);

const long m = 1000000007;
long det;

int main()
{
    long a, b, n;
    cin >> a >> b >> n;
    matrix cache, x;
    cache.x11 = a;
    cache.x12 = b;
    cache.x21 = 1;
    cache.x22 = 0;
    x.x11 = 1;
    x.x12 = 0;
    x.x21 = 0;
    x.x22 = 1;
    while (n > 0) {
        if (n % 2 == 1) {
            x = mul(x, cache);
        }
        cache = mul(cache, cache);
        n /= 2;
    }
    cout << x.x21 << endl;
}

matrix mul(matrix x, matrix y)
{
    matrix z;
    z.x11 = (x.x11 * y.x11 % m + x.x12 * y.x21 % m) % m;
    z.x12 = (x.x11 * y.x12 % m + x.x12 * y.x22 % m) % m;
    z.x21 = (x.x21 * y.x11 % m + x.x22 * y.x21 % m) % m;
    z.x22 = (x.x21 * y.x12 % m + x.x22 * y.x22 % m) % m;
    return z;
}