#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> p_ll;

template<class T>
void debug(T itr1, T itr2) { auto now = itr1; while(now<itr2) { cout << *now << " "; now++; } cout << endl; }
#define repr(i,from,to) for (ll i=(ll)from; i<(ll)to; i++)
#define all(vec) vec.begin(), vec.end()
#define rep(i,N) repr(i,0,N)
#define per(i,N) for (int i=(int)N-1; i>=0; i--)

const ll MOD = pow(10,9)+7;
const ll LLINF = pow(2,61)-1;
const int INF = pow(2,30)-1;

vector<ll> fac;
void c_fac(int x=pow(10,6)+10) { fac.resize(x,true); rep(i,x) fac[i] = i ? (fac[i-1]*i)%MOD : 1; }
ll modpow(ll x, ll p) { ll result = 1, now = 1, pm = x; while (now<=p) { if (p&now) { result = result * pm % MOD; } now*=2; pm = pm*pm % MOD; } return result; }
ll inv(ll a, ll m=MOD) { ll b = m, x = 1, y = 0; while (b!=0) { int d = a/b; a -= b*d; swap(a,b); x -= y*d; swap(x,y); } return (x+m)%m; }
ll nck(ll n, ll k) { return fac[n]*inv(fac[k]*fac[n-k]%MOD)%MOD; }
ll gcd(ll a, ll b) { if (a<b) swap(a,b); return b==0 ? a : gcd(b, a%b); }
ll lcm(ll a, ll b) { return a/gcd(a,b)*b; }

// ----------------------------------------------------------------------
// ----------------------------------------------------------------------

vector<vector<ll>> matsum(vector<vector<ll>> A, vector<vector<ll>> B) {
  if (A.size()!=B.size()||A[0].size()!=B[0].size()) return {{}};
  ll h = A.size(), w = A[0].size();
  vector<vector<ll>> result(h,vector<ll>(w,0));
  rep(i,h) rep(j,w) result[i][j] = (A[i][j]+B[i][j])%MOD;
  return result;
}

vector<vector<ll>> matdiff(vector<vector<ll>> A, vector<vector<ll>> B) {
  if (A.size()!=B.size()||A[0].size()!=B[0].size()) return {{}};
  ll h = A.size(), w = A[0].size();
  vector<vector<ll>> result(h,vector<ll>(w,0));
  rep(i,h) rep(j,w) result[i][j] = (MOD+(A[i][j]-B[i][j])%MOD)%MOD;
  return result;
}

vector<vector<ll>> matdot(vector<vector<ll>> A, vector<vector<ll>> B) {
  if (A[0].size()!=B.size()) return {{}};
  ll h = A.size(), w = B[0].size(), x = A[0].size();
  vector<vector<ll>> result(h,vector<ll>(w,0));
  rep(i,h) rep(j,w) rep(k,x) result[i][j] = (result[i][j] + A[i][k]*B[k][j])%MOD;
  return result;
}

vector<vector<ll>> matpow(vector<vector<ll>> A, ll n) {
  if (A.size()!=A[0].size()) return {{}};
  int N = A.size();
  vector<vector<ll>> result(N,vector<ll>(N,0)), now;
  copy(all(A),back_inserter(now));
  rep(i,N) result[i][i] = 1;
  ll p2 = 1; 
  while (n>=p2) {
    if (n&p2) result = matdot(result,now);
    now = matdot(now,now); p2 *= 2;
  }
  return result;
}

// ----------------------------------------------------------------------
// ----------------------------------------------------------------------

int main() {
  ll a, b, n; cin >> a >> b >> n;
  ll result = 2;
  if (n!=0) {
    vector<vector<ll>> mat = { {2*a%MOD, (b-a*a%MOD+MOD)%MOD}, {1, 0} };
    vector<vector<ll>> a01 = { {2*a%MOD} , {2} };
    vector<vector<ll>> md  = matdot(matpow(mat, n-1), a01);
    result = md[0][0];
  }
  cout << result << endl;
  return 0;
}