#pragma GCC optimize("Ofast")
#include<bits/stdc++.h>
//#include<boost/multiprecision/cpp_int.hpp>
//#include<boost/multiprecision/cpp_dec_float.hpp>
//namespace mp=boost::multiprecision;
//#define mulint mp::cpp_int
//#define mulfloat mp::cpp_dec_float_100
using namespace std;
struct __INIT{__INIT(){cin.tie(0);ios::sync_with_stdio(false);cout<<fixed<<setprecision(15);}} __init;
#define max3(a,b,c) max(a,max(b,c))
#define min3(a,b,c) min(a,min(b,c))
constexpr int MOD=1000000007;
//constexpr int MOD=998244353;
#define INF (1<<30)
#define LINF (lint)(1LL<<56)
#define endl "\n"
#define rep(i,n) for(lint (i)=0;(i)<(n);(i)++)
#define reprev(i,n) for(lint (i)=(n-1);(i)>=0;(i)--)
#define Flag(x) (1<<(x))
#define Flagcount(x) __builtin_popcountll(x)
#define pint pair<int,int>
#define pdouble pair<double,double>
#define plint pair<lint,lint>
#define fi first
#define se second
typedef long long lint;
int dx[8]={1,1,0,-1,-1,-1,0,1};
int dy[8]={0,1,1,1,0,-1,-1,-1};
const int MAX_N=2e5+5;
//struct edge{lint to,num;};
//vector<int> bucket[MAX_N/1000];

typedef vector<vector<lint>> mat;
 
mat mtx{
    {1,1},
    {1,0},
};
 
vector<lint> F{0,1}; //F(1)~F(K)の値
 
mat mul(mat &A,mat &B){
    mat C(A.size(),vector<lint>(B[0].size()));
    rep(i,A.size()) rep(j,B.size()) rep(k,B[0].size()){
        C[i][k]=(C[i][k]+A[i][j]*B[j][k])%MOD; //演算 適宜演算子を変える
    }
    return C;
}
 
mat powmat(mat A,lint n){
    mat B(A.size(),vector<lint>(A.size()));
    rep(i,A.size()) B[i][i]=1; //単位元 零元が0じゃない時はそこも自分で埋める
    while(n){
        if(n&1) B=mul(B,A);
        A=mul(A,A);
        n>>=1;
    }
    return B;
}

mat powmatsum(mat A,lint n){ //A+A^2+...+A^Nを返す
    mat B(A.size()*2,vector<lint>(A.size()*2));
    rep(i,A.size()) rep(j,A.size()) B[i][j]=A[i][j];
    rep(i,A.size()) B[A.size()+i][i]=B[A.size()+i][A.size()+i]=1;
    B=powmat(B,n+1);
    rep(i,A.size()) B[A.size()+i][i]=(B[A.size()+i][i]-1+MOD)%MOD;
    mat res(A.size(),vector<lint>(A.size()));
    rep(i,A.size()) rep(j,A.size()) res[i][j]=B[A.size()+i][j];
    return res;
}
 
lint calc(lint n,mat A=mtx,vector<lint> f=F){ //F(N)の計算
    if(n==0) return 0;
    A=powmat(A,n-1);
    lint res=0; //零元
    rep(i,A.size()) res=(res+A[A.size()-1][i]*f[A.size()-1-i])%MOD;//演算 適宜演算子を変える
    return res;
}

lint calcsum(lint n,mat A=mtx,vector<lint> f=F){ //Σ[i=1..N]F(i)の計算
    if(n==0) return 0;
    mat B(A.size()*2,vector<lint>(A.size()*2));
    rep(i,A.size()) rep(j,A.size()) B[i][j]=A[i][j];
    rep(i,A.size()) B[A.size()+i][i]=B[A.size()+i][A.size()+i]=1;
    B=powmat(B,n);
    rep(i,A.size()) B[A.size()+i][i]=(B[A.size()+i][i]-1+MOD)%MOD;
    lint res=0; //零元
    rep(i,A.size()) res=(res+B[A.size()*2-1][i]*f[A.size()-1-i])%MOD;//演算 適宜演算子を変える
    return res;
}
 
 
/*
定数項がある場合、定数をXとして
    {1,0,1,X},//F(N-1),F(N-2),...,F(N-K)の係数,X
    {1,0,0,0},
    {0,1,0,0},
    {0,0,0,1}.
 
    F{1,f1,f2,f3};
答えの計算パートが
rep(i,A.size()) res=(res+A[A.size()-2][i]*F[A.size()-1-i])%MOD;
となる
累乗和のときは 
rep(i,A.size()) res=(res+B[A.size()*2-2][i]*f[A.size()-1-i])%MOD;
*/

int main(void){
    lint N;
    cin >> mtx[0][0] >> mtx[0][1] >> N;
    cout << calc(N+1) << endl;
}