using System;
using System.Collections.Generic;
using System.IO;
using System.Numerics;
class Solution {
    static void Main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution */
        string[] input = Console.ReadLine().Split(' ');
        BigInteger a = new BigInteger(Int32.Parse(input[0]));
        BigInteger b = new BigInteger(Int32.Parse(input[1]));
        BigInteger t = new BigInteger(Int32.Parse(input[2]));
        BigInteger result = new BigInteger(0);
        BigInteger modulo = new BigInteger(1000000007);
        BigInteger half = new BigInteger(2);
        result = power(a, t, modulo, half) + power(b, t, modulo, half);
        //result *= half; 
        Console.WriteLine(result);               
    }
    static BigInteger power(BigInteger a, BigInteger t, BigInteger mod, BigInteger half){
        BigInteger res = new BigInteger(1);
        BigInteger even = new BigInteger(2);
        a = a % mod;  
        
        while (t > 0){
            if(t % even != new BigInteger(0)){
                res = (res * a)%mod;
            }
            t = t >> 1;
            a = (a * a) % mod;
        }
        return res / half;           
    }
}