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

int mod = 1000000007;

vector<vector<long long>> Mul(vector<vector<long long>> A,vector<vector<long long>> B) {
    vector<vector<long long>>ans(A.size(),vector<long long>(A.size()));
    for(int i = 0; i < A.size(); i++) {
        for(int j = 0; j < A.size(); j++) {
            for(int k = 0; k < A.size(); k++) {
                ans[i][j] += A[i][k]*B[k][j]%mod;
                ans[i][j] %= mod;
            }
        }
    }
    return ans;
}

vector<vector<long long>> Pow(vector<vector<long long>> A,long long B) {
    vector<vector<long long>>ans(A.size(),vector<long long>(A.size()));
    for(int i = 0; i < A.size(); i++) {
        ans[i][i] = 1;
    }
    while (B) {
        if(1 & B) {
            ans = Mul(ans,A);
        }
        A = Mul(A,A);
        B /= 2;
    }
    return ans;
}

int main() {
    int a,b,n;
    cin >> a >> b >> n;
    vector<vector<long long>>tmp(2,vector<long long>(2));
    tmp[0][0] = a;
    tmp[0][1] = b;
    tmp[1][0] = 1;
    tmp = Pow(tmp,n);
    cout << tmp[1][0] << endl;
}