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

class mixed {
public:
  long re, im;
};

mixed mul(mixed, mixed);

const long m = 1000000007;
long det;

int main()
{
  long a, b, n;
  cin >> a >> b >> n;
  long ahalf = a % 2 == 0 ? a / 2 : (a + m) / 2;
  det = (ahalf * ahalf % m + b) % m;
  mixed alpha, x, cache;
  alpha.re = ahalf;
  alpha.im = 1;
  x.re = 1;
  x.im = 0;
  cache = alpha;
  while (n > 0) {
    if (n % 2 == 1) {
      x = mul(x, cache);
    }
    cache = mul(cache, cache);
    n /= 2;
  }
  cout << x.im << endl;
}

mixed mul(mixed x, mixed y)
{
  mixed z;
  z.re = (x.re * y.re % m + det * (x.im * y.im % m) % m) % m;
  z.im = (x.re * y.im % m + x.im * y.re % m) % m;
  return z;
}