#pragma GCC optimize ("Ofast")
#include<bits/stdc++.h>
using namespace std;
#define MD 1000000007
void *wmem;
char memarr[96000000];
template<class S, class T> inline S min_L(S a,T b){
  return a<=b?a:b;
}
struct mint{
  static unsigned md;
  static unsigned W;
  static unsigned R;
  static unsigned Rinv;
  static unsigned mdninv;
  static unsigned RR;
  unsigned val;
  mint(){
  }
  mint(int a){
    val = mulR(a);
  }
  mint(unsigned a){
    val = mulR(a);
  }
  mint(long long a){
    val = mulR(a);
  }
  mint(unsigned long long a){
    val = mulR(a);
  }
  int get_inv(long long a, int md){
    long long t=a;
    long long s=md;
    long long u=1;
    long long v=0;
    long long e;
    while(s){
      e=t/s;
      t-=e*s;
      u-=e*v;
      swap(t,s);
      swap(u,v);
    }
    if(u<0){
      u+=md;
    }
    return u;
  }
  void setmod(unsigned m){
    int i;
    unsigned t;
    W = 32;
    md = m;
    R = (1ULL << W) % md;
    RR = (unsigned long long)R*R % md;
    switch(m){
      case 104857601:
      Rinv = 2560000;
      mdninv = 104857599;
      break;
      case 998244353:
      Rinv = 232013824;
      mdninv = 998244351;
      break;
      case 1000000007:
      Rinv = 518424770;
      mdninv = 2226617417U;
      break;
      case 1000000009:
      Rinv = 171601999;
      mdninv = 737024967;
      break;
      case 1004535809:
      Rinv = 234947584;
      mdninv = 1004535807;
      break;
      case 1007681537:
      Rinv = 236421376;
      mdninv = 1007681535;
      break;
      case 1012924417:
      Rinv = 238887936;
      mdninv = 1012924415;
      break;
      case 1045430273:
      Rinv = 254466304;
      mdninv = 1045430271;
      break;
      case 1051721729:
      Rinv = 257538304;
      mdninv = 1051721727;
      break;
      default:
      Rinv = get_inv(R, md);
      mdninv = 0;
      t = 0;
      for(i=(0);i<((int)W);i++){
        if(t%2==0){
          t+=md;
          mdninv |= (1U<<i);
        }
        t /= 2;
      }
    }
  }
  unsigned mulR(unsigned a){
    return (unsigned long long)a*R%md;
  }
  unsigned mulR(int a){
    if(a < 0){
      a = a%((int)md)+(int)md;
    }
    return mulR((unsigned)a);
  }
  unsigned mulR(unsigned long long a){
    return mulR((unsigned)(a%md));
  }
  unsigned mulR(long long a){
    a %= md;
    if(a < 0){
      a += md;
    }
    return mulR((unsigned)a);
  }
  unsigned reduce(unsigned T){
    unsigned m = T * mdninv;
    unsigned t = (unsigned)((T + (unsigned long long)m*md) >> W);
    if(t >= md){
      t -= md;
    }
    return t;
  }
  unsigned reduce(unsigned long long T){
    unsigned m = (unsigned)T * mdninv;
    unsigned t = (unsigned)((T + (unsigned long long)m*md) >> W);
    if(t >= md){
      t -= md;
    }
    return t;
  }
  unsigned get(){
    return reduce(val);
  }
  mint &operator+=(mint a){
    val += a.val;
    if(val >= md){
      val -= md;
    }
    return *this;
  }
  mint &operator-=(mint a){
    if(val < a.val){
      val = val + md - a.val;
    }
    else{
      val -= a.val;
    }
    return *this;
  }
  mint &operator*=(mint a){
    val = reduce((unsigned long long)val*a.val);
    return *this;
  }
  mint &operator/=(mint a){
    return *this *= a.inverse();
  }
  mint operator+(mint a){
    return mint(*this)+=a;
  }
  mint operator-(mint a){
    return mint(*this)-=a;
  }
  mint operator*(mint a){
    return mint(*this)*=a;
  }
  mint operator/(mint a){
    return mint(*this)/=a;
  }
  mint operator+(int a){
    return mint(*this)+=mint(a);
  }
  mint operator-(int a){
    return mint(*this)-=mint(a);
  }
  mint operator*(int a){
    return mint(*this)*=mint(a);
  }
  mint operator/(int a){
    return mint(*this)/=mint(a);
  }
  mint operator+(long long a){
    return mint(*this)+=mint(a);
  }
  mint operator-(long long a){
    return mint(*this)-=mint(a);
  }
  mint operator*(long long a){
    return mint(*this)*=mint(a);
  }
  mint operator/(long long a){
    return mint(*this)/=mint(a);
  }
  mint operator-(void){
    mint res;
    if(val){
      res.val=md-val;
    }
    else{
      res.val=0;
    }
    return res;
  }
  operator bool(void){
    return val!=0;
  }
  operator int(void){
    return get();
  }
  operator long long(void){
    return get();
  }
  mint inverse(){
    int a = val;
    int b = md;
    int u = 1;
    int v = 0;
    int t;
    mint res;
    while(b){
      t = a / b;
      a -= t * b;
      swap(a, b);
      u -= t * v;
      swap(u, v);
    }
    if(u < 0){
      u += md;
    }
    res.val = (unsigned long long)u*RR % md;
    return res;
  }
  mint pw(unsigned long long b){
    mint a(*this);
    mint res;
    res.val = R;
    while(b){
      if(b&1){
        res *= a;
      }
      b >>= 1;
      a *= a;
    }
    return res;
  }
  bool operator==(int a){
    return mulR(a)==val;
  }
  bool operator!=(int a){
    return mulR(a)!=val;
  }
}
;
unsigned mint::md;
unsigned mint::W;
unsigned mint::R;
unsigned mint::Rinv;
unsigned mint::mdninv;
unsigned mint::RR;
mint operator+(int a, mint b){
  return mint(a)+=b;
}
mint operator-(int a, mint b){
  return mint(a)-=b;
}
mint operator*(int a, mint b){
  return mint(a)*=b;
}
mint operator/(int a, mint b){
  return mint(a)/=b;
}
mint operator+(long long a, mint b){
  return mint(a)+=b;
}
mint operator-(long long a, mint b){
  return mint(a)-=b;
}
mint operator*(long long a, mint b){
  return mint(a)*=b;
}
mint operator/(long long a, mint b){
  return mint(a)/=b;
}
inline void rd(int &x){
  int k;
  int m=0;
  x=0;
  for(;;){
    k = getchar_unlocked();
    if(k=='-'){
      m=1;
      break;
    }
    if('0'<=k&&k<='9'){
      x=k-'0';
      break;
    }
  }
  for(;;){
    k = getchar_unlocked();
    if(k<'0'||k>'9'){
      break;
    }
    x=x*10+k-'0';
  }
  if(m){
    x=-x;
  }
}
inline void rd(mint &x){
  int i;
  rd(i);
  x=i;
}
inline void wt_L(char a){
  putchar_unlocked(a);
}
inline void wt_L(int x){
  int s=0;
  int m=0;
  char f[10];
  if(x<0){
    m=1;
    x=-x;
  }
  while(x){
    f[s++]=x%10;
    x/=10;
  }
  if(!s){
    f[s++]=0;
  }
  if(m){
    putchar_unlocked('-');
  }
  while(s--){
    putchar_unlocked(f[s]+'0');
  }
}
inline void wt_L(mint x){
  int i;
  i = (int)x;
  wt_L(i);
}
template<class T> struct Matrix{
  int r;
  int c;
  int mem;
  T *dat;
  Matrix(){
    r=c=mem = 0;
  }
  Matrix(const int rr, const int cc){
    if(rr == 0 || cc == 0){
      r = c = 0;
    }
    else{
      r = rr;
      c = cc;
    }
    mem = r * c;
    if(mem > 0){
      dat = new T[mem];
    }
  }
  Matrix(const Matrix<T> &a){
    int i;
    r = a.r;
    c = a.c;
    mem = r * c;
    dat = new T[mem];
    for(i=(0);i<(mem);i++){
      dat[i] = a.dat[i];
    }
  }
  ~Matrix(){
    if(mem){
      delete [] dat;
    }
  }
  void changeSize(const int rr, const int cc){
    if(rr==0 || cc==0){
      r = c = 0;
    }
    else{
      r = rr;
      c = cc;
    }
    if(mem < r*c){
      if(mem){
        delete [] dat;
      }
      mem = r*c;
      dat = new T[mem];
    }
  }
  Matrix<T>& operator=(const Matrix<T> &a){
    int i;
    int j;
    r = a.r;
    c = a.c;
    mem = r * c;
    dat = new T[mem];
    for(i=(0);i<(mem);i++){
      dat[i] = a.dat[i];
    }
    return *this;
  }
  Matrix<T>& operator=(const int a){
    int i;
    int j;
    j = r * c;
    for(i=(0);i<(j);i++){
      dat[i] = 0;
    }
    j =min_L(r, c);
    for(i=(0);i<(j);i++){
      dat[i*c+i] = a;
    }
    return *this;
  }
  Matrix<T>& operator+=(const Matrix<T> &a){
    int i;
    int j;
    if(r==0 || r!=a.r || c!=a.c){
      changeSize(0,0);
      return *this;
    }
    j = r*c;
    for(i=(0);i<(j);i++){
      dat[i] += a.dat[i];
    }
    return *this;
  }
  Matrix<T> operator+(const Matrix<T> &a){
    return Matrix<T>(*this) += a;
  }
  Matrix<T>& operator-=(const Matrix<T> &a){
    int i;
    int j;
    if(r==0 || r!=a.r || c!=a.c){
      changeSize(0,0);
      return *this;
    }
    j = r*c;
    for(i=(0);i<(j);i++){
      dat[i] -= a.dat[i];
    }
    return *this;
  }
  Matrix<T> operator-(const Matrix<T> &a){
    return Matrix<T>(*this) -= a;
  }
  Matrix<T>& operator*=(const Matrix<T> &a){
    int i;
    int j;
    int k;
    int x;
    T *m;
    if(r==0 || c!=a.r){
      changeSize(0,0);
      return *this;
    }
    m = (T*)wmem;
    x = r * a.c;
    for(i=(0);i<(x);i++){
      m[i] = 0;
    }
    for(i=(0);i<(r);i++){
      for(k=(0);k<(c);k++){
        for(j=(0);j<(a.c);j++){
          m[i*a.c+j] += dat[i*c+k] * a.dat[k*a.c+j];
        }
      }
    }
    changeSize(r, a.c);
    for(i=(0);i<(x);i++){
      dat[i] = m[i];
    }
    return *this;
  }
  Matrix<T> operator*(const Matrix<T> &a){
    return Matrix<T>(*this) *= a;
  }
  Matrix<T>& operator*=(const int a){
    int i;
    int j;
    j = r * c;
    for(i=(0);i<(j);i++){
      dat[i] *= a;
    }
    return *this;
  }
  Matrix<T>& operator*=(const long long a){
    int i;
    int j;
    j = r * c;
    for(i=(0);i<(j);i++){
      dat[i] *= a;
    }
    return *this;
  }
  Matrix<T>& operator*=(const double a){
    int i;
    int j;
    j = r * c;
    for(i=(0);i<(j);i++){
      dat[i] *= a;
    }
    return *this;
  }
  inline T* operator[](const int a){
    return dat+a*c;
  }
}
;
template<class T> Matrix<T> operator*(const int a, const Matrix<T> &b){
  return Matrix<T>(b)*=a;
}
template<class T> Matrix<T> operator*(const Matrix<T> &b, const int a){
  return Matrix<T>(b)*=a;
}
template<class T> Matrix<T> operator*(const long long a, const Matrix<T> &b){
  return Matrix<T>(b)*=a;
}
template<class T> Matrix<T> operator*(const Matrix<T> &b, const long long a){
  return Matrix<T>(b)*=a;
}
template<class T> Matrix<T> operator*(const double a, const Matrix<T> &b){
  return Matrix<T>(b)*=a;
}
template<class T> Matrix<T> operator*(const Matrix<T> &b, const double a){
  return Matrix<T>(b)*=a;
}
template<class T, class S> inline Matrix<T> pow_L(Matrix<T> a, S b){
  int i;
  int j;
  Matrix<T> res;
  res.changeSize(a.r, a.c);
  res = 1;
  while(b){
    if(b&1){
      res *= a;
    }
    b >>= 1;
    a *= a;
  }
  return res;
}
template<class T, class S> inline T pow_L(T a, S b){
  T res = 1;
  res = 1;
  while(b){
    if(b&1){
      res *= a;
    }
    b >>= 1;
    a *= a;
  }
  return res;
}
inline double pow_L(double a, double b){
  return pow(a,b);
}
int N;
mint A;
mint B;
int main(){
  wmem = memarr;
  {
    mint x;
    x.setmod(MD);
  }
  Matrix<mint> m;
  rd(A);
  rd(B);
  rd(N);
  if(N==0){
    wt_L(0);
    wt_L('\n');
    return 0;
  }
  m.changeSize(2,2);
  m[0][0] = 0;
  m[0][1] = 1;
  m[1][0] = B;
  m[1][1] = A;
  (m = pow_L(m,N));
  wt_L(m[0][1]);
  wt_L('\n');
  return 0;
}
// cLay varsion 20190919-1 [beta]

// --- original code ---
// int N;
// mint A, B;
// {
//   Matrix<mint> m;
//   rd(A,B,N);
//   if(N==0) wt(0), return 0;
//   m.changeSize(2,2);
//   m[0][0] = 0;
//   m[0][1] = 1;
//   m[1][0] = B;
//   m[1][1] = A;
//   m **= N;
//   wt(m[0][1]);
// }