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

public class Solution {

    public static void main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
        Scanner in = new Scanner(System.in);
        int a = in.nextInt();
        int b = in.nextInt();
        int t = in.nextInt();
        int cells = 1;
        for(int i=0; i<t; i++){
            cells = (int)((0.5 * a * cells) + (0.5 * b * cells));
        }
        System.out.println((int)(cells%(Math.pow(10,9)+7)));
    }
}