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 scanner = new Scanner(System.in);
        int a=0,b=0,t=0;
        int noOfVirusCells = 1;
        
        int modulo = (int)(Math.pow(10,9) + 7);
        
        if(scanner.hasNext()){
            a = scanner.nextInt();
            b = scanner.nextInt();
            t = scanner.nextInt();
        }
        
        for(int i=0;i<t;i++){
            noOfVirusCells = ((int)(0.5 * a * noOfVirusCells))%modulo + ((int)(0.5 * b * noOfVirusCells))%modulo;
        }
        
        System.out.println(noOfVirusCells%modulo);
        
    }
}