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

typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> P;

#define fi first
#define se second
#define repl(i,a,b) for(ll i=(ll)(a);i<(ll)(b);i++)
#define rep(i,n) repl(i,0,n)
#define all(x) (x).begin(),(x).end()
#define dbg(x) cout<<#x"="<<x<<endl
#define mmax(x,y) (x>y?x:y)
#define mmin(x,y) (x<y?x:y)
#define maxch(x,y) x=mmax(x,y)
#define minch(x,y) x=mmin(x,y)
#define uni(x) x.erase(unique(all(x)),x.end())
#define exist(x,y) (find(all(x),y)!=x.end())
#define bcnt __builtin_popcountll

#define INF 1e16
#define mod 1000000007

typedef vector<ll> vec;
typedef vector<vec> mat;

mat operator*(const mat& a,const mat& b){
  ll n=a.size();
  mat res(n,vec(n,0));
  rep(i,n)rep(j,n)rep(k,n)(res[i][j]+=(a[i][k]*b[k][j]%mod))%=mod;
  return res;
}

mat mod_pow(mat a,ll n){
  ll m=a.size();
  mat res(m,vec(m,0));
  rep(i,m)res[i][i]=1;
  while(n>0){
    if(n&1)res=a*res;
    a=a*a;
    n>>=1;
  }
  return res;
}

int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);

  ll a,b,n;
  cin>>a>>b>>n;
  if(n==0){
    cout<<0<<endl;
    return 0;
  }

  mat A(2,vec(2,0));
  A[0][0]=a; A[0][1]=b;
  A[1][0]=1; A[1][1]=0;

  mat B=mod_pow(A,n-1);
  cout<<B[0][0]<<endl;

  return 0;
}