import java.util.*;
import java.io.*;
public class Main {
    public static void main(String[]args){
		Scanner sc = new Scanner(System.in);
		PrintWriter ou = new PrintWriter(System.out);
		long a = Long.parseLong(sc.next());
		int b = Integer.parseInt(sc.next());
		int n = Integer.parseInt(sc.next());
		sc.close();
		if(n == 0) ou.println(2);
		else{
			long[] q = new long[n + 1];
			q[0] = 2;
			q[1] = 2 * a;
			for(int i = 2 ; i <= n ; i++){
				q[i] = ((2 * a * (long)q[i - 1] - (a * (long)a - b) * q[i - 2]) % (int)(Math.pow(10 , 9) + 7));
			}
			while(q[n] < 0) q[n] += (long)Math.pow(10 , 9) + 7;
			ou.println(q[n]);
		}
		ou.flush();
	}
}