#include "bits/stdc++.h"

#define MOD 1000000007
#define rep(i, n) for(ll i=0; i < (n); i++)
#define rrep(i, n) for(ll i=(n)-1; i >=0; i--)
#define ALL(v) v.begin(),v.end()
#define rALL(v) v.rbegin(),v.rend()
#define FOR(i, j, k) for(ll i=j;i<k;i++)
#define debug_print(var) cerr << #var << "=" << var <<endl;
#define DUMP(i, v)for(ll i=0;i<v.size();i++)cerr<<v[i]<<" "
#define fi first
#define se second

using namespace std;
typedef long long int ll;
typedef vector<ll> llvec;
typedef vector<double> dvec;
typedef pair<ll, ll> P;
typedef long double ld;
struct edge{ll x, c;};
using mat = vector<llvec>;

/**************************************
** A main function starts from here  **
***************************************/
int main(){
  ll a, b, n;
  cin >> a >> b >> n;
  mat e = {{1, 0}, {0, 1}};
  mat A = {{a, b}, {1, 0}};
  auto prod =[](mat a, mat b){
    mat ans(2, llvec(2, 0));
    rep(i, 2)rep(j, 2)rep(k, 2){
      ans[i][j] += a[i][k]*b[k][j];
      ans[i][j] %=MOD;
    }
    return ans;
  };
  if(n==1){
    cout << 1 << endl;
    return 0;
  }else if(n==0){
    cout << 0 << endl;
    return 0;
  }
  n-=1;
  while(n>0){
    if(n%2==1){
      e = prod(A, e);
    }
    A = prod(A, A);
    n/=2;
  }
  cout << (e[0][0])%MOD<<endl;
  return 0;
}