#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<bitset>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<deque>
#include<list>
#include<iomanip>
#include<cmath>
#include<cstring>
#include<functional>
#include<cstdio>
#include<cstdlib>
using namespace std;

#define repr(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define rep(i, n) repr(i, 0, n)
#define INF 2e9
#define MOD 1000000007
//#define MOD 998244353
#define LINF (long long)4e18
#define jck 3.141592

const double EPS = 1e-10;

using ll = long long;
using Pi = pair<int,int>;
using Pl = pair<ll,ll>;

template<typename T>
struct Mat{
    vector<vector<T>> val;
    Mat(int n, int m, T x = 0) : val(n,vector<T>(m,x)){}
    void init(int n, int m, T x = 0){
        val.assign(n,vector<T>(m,x));
    }
    size_t size(){
        return val.size();
    }
    inline vector<T>& operator [](int i){
        return val[i];
    }
};

Mat<ll> operator *(Mat<ll> A, Mat<ll> B){
    Mat<ll> R(A.size(),B[0].size());
    for(int i = 0; i < A.size(); i++){
        for(int j = 0; j < B[0].size(); j++){
            for(int k = 0; k < B.size(); k++){
                R[i][j] += A[i][k]*B[k][j]+MOD;
                R[i][j] %= MOD;
            }
        }
    }
    return R;
}

Mat<ll> pow(Mat<ll> A, ll n){
    Mat<ll> R(A.size(),A.size());
    for(int i = 0; i < A.size(); i++) R[i][i] = 1;
    while(n > 0){
        if(n&1) R = R*A;
        A = A*A;
        n >>= 1;
    }
    return R;
}
int main(){
    ll a,b,n; cin >> a >> b >> n;
    Mat<ll> mat(2,2);
    mat[0][0] = a;
    mat[0][1] = b;
    mat[1][0] = 1;
    Mat<ll> mat2 = pow(mat,n);
    cout << mat2[1][0] << endl;
}