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

const int MOD = 1e9 + 7;

vector<vector<int>> mmul(vector<vector<int>> a, vector<vector<int>> b) {
  vector<vector<int>> c(a.size(), vector<int>(b[0].size()));
  for (int i = 0; i < a.size(); ++i) {
    for (int j = 0; j < b.size(); ++j) {
      for (int k = 0; k < b[0].size(); ++k) {
        (c[i][k] += 1LL * a[i][j] * b[j][k] % MOD) %= MOD;
      }
    }
  }
  return c;
}

vector<vector<int>> mpow(vector<vector<int>> a, int n) {
  vector<vector<int>> r(a.size(), vector<int>(a.size()));
  for (int i = 0; i < a.size(); ++i) r[i][i] = 1;
  for (int i = n; i; i >>= 1) {
    if (i & 1) r = mmul(r, a);
    a = mmul(a, a);
  }
  return r;
}

int main() {
  int A, B, N;
  cin >> A >> B >> N;

  vector<vector<int>> t({ { A, B }, { 1, 0 } });
  vector<vector<int>> a0({ { 1 }, { 0 } });

  int an = mmul(mpow(t, N), a0)[1][0];
  cout << an << endl;

  return 0;
}