import java.io.*;
import java.util.*;

public class Solution {

    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        int a = s.nextInt();
        int b = s.nextInt();
        long t = s.nextLong();
        
        long c = (a + b) / 2;
        List<Long> extra = new ArrayList<Long>();
        while (t != 1) {
        	if (t % 2 == 1)
        		extra.add(c);
        	t = t / 2;
        	c = (c * c) % 1000000007;
        }
        for (long l : extra) {
        	c = (c * l) % 1000000007;
        }
        System.out.println(c);
    }
}