#include<bits/stdc++.h>
using namespace std;
using Int = long long;
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}


template<typename R>
struct Kitamasa{
  using VR = vector<R>;
  VR c;
  vector<VR> rs;
  Int m;

  Kitamasa(const VR &C)
    :c(C),rs(1),m(c.size()){
    rs[0].assign(2*m+1,R::add_identity());
    rs[0][1]=R::mul_identity();
  }

  VR merge(const VR &x,const VR &y){
    VR z(2*m+1,R::add_identity());
    for(Int i=1;i<=m;i++)
      for(Int j=1;j<=m;j++)
        z[i+j]=z[i+j]+(x[i]*y[j]);

    for(Int i=2*m;i>m;z[i--]=R::add_identity())
      for(Int j=1;j<=m;j++)
        z[i-j]=z[i-j]+(c[m-j]*z[i]);
    return z;
  }

  R calc(const VR &A,long long n){
    assert((Int)A.size()==m);
    VR res(rs[0]);
    for(Int i=0;n;i++,n>>=1){
      if(i>=(Int)rs.size())
        rs.emplace_back(merge(rs[i-1],rs[i-1]));
      if(~n&1) continue;
      res=merge(res,rs[i]);
    }
    R ans=R::add_identity();
    for(Int i=1;i<=m;i++) ans=ans+(res[i]*A[i-1]);
    return ans;
  }
};


template<typename T,T MOD = 1000000007>
struct Mint{
  static constexpr T mod = MOD;
  T v;
  Mint():v(0){}
  Mint(signed v):v(v){}
  Mint(long long t){v=t%MOD;if(v<0) v+=MOD;}

  Mint pow(long long k){
    Mint res(1),tmp(v);
    while(k){
      if(k&1) res*=tmp;
      tmp*=tmp;
      k>>=1;
    }
    return res;
  }

  static Mint add_identity(){return Mint(0);}
  static Mint mul_identity(){return Mint(1);}

  Mint inv(){return pow(MOD-2);}

  Mint& operator+=(Mint a){v+=a.v;if(v>=MOD)v-=MOD;return *this;}
  Mint& operator-=(Mint a){v+=MOD-a.v;if(v>=MOD)v-=MOD;return *this;}
  Mint& operator*=(Mint a){v=1LL*v*a.v%MOD;return *this;}
  Mint& operator/=(Mint a){return (*this)*=a.inv();}

  Mint operator+(Mint a) const{return Mint(v)+=a;};
  Mint operator-(Mint a) const{return Mint(v)-=a;};
  Mint operator*(Mint a) const{return Mint(v)*=a;};
  Mint operator/(Mint a) const{return Mint(v)/=a;};

  Mint operator-() const{return v?Mint(MOD-v):Mint(v);}

  bool operator==(const Mint a)const{return v==a.v;}
  bool operator!=(const Mint a)const{return v!=a.v;}
  bool operator <(const Mint a)const{return v <a.v;}

  // find x s.t. a^x = b
  static T log(T a,T b){
    const T sq=40000;
    unordered_map<T, T> dp;
    dp.reserve(sq);
    Mint res(1);
    for(Int r=0;r<sq;r++){
      if(!dp.count(res.v)) dp[res.v]=r;
      res*=a;
    }
    Mint p=Mint(a).inv().pow(sq);
    res=b;
    for(Int q=0;q<=MOD/sq+1;q++){
      if(dp.count(res.v)){
        T idx=q*sq+dp[res.v];
        if(idx>0) return idx;
      }
      res*=p;
    }
    assert(0);
    return T(-1);
  }

  static Mint comb(long long n,Int k){
    Mint num(1),dom(1);
    for(Int i=0;i<k;i++){
      num*=Mint(n-i);
      dom*=Mint(i+1);
    }
    return num/dom;
  }
};
template<typename T,T MOD> constexpr T Mint<T, MOD>::mod;
template<typename T,T MOD>
ostream& operator<<(ostream &os,Mint<T, MOD> m){os<<m.v;return os;}

//INSERT ABOVE HERE
signed main(){
  Int a,b,n;
  cin>>a>>b>>n;

  using M = Mint<Int>;
  vector<M> C({M(b),M(a)});
  Kitamasa<M> kt(C);

  vector<M> A({M(0),M(1)});
  cout<<kt.calc(A,n)<<endl;
  return 0;
}