import java.io.*;
import java.util.*;
import java.math.BigInteger;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        
        BigInteger a = new BigInteger(in.next());
        BigInteger b = new BigInteger(in.next());
        BigInteger t = new BigInteger(in.next());
        
        System.out.println(a.add(b).divide(BigInteger.valueOf(2)).modPow(t, BigInteger.valueOf(1000000007)));
    }
}