import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

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. */
//    	System.out.println(Integer.MAX_VALUE);
//    	System.out.println(Integer.MAX_VALUE - Math.pow(10, 9) + 7);
        Scanner scan = new Scanner(System.in);
        String inputs = scan.nextLine();
    	System.out.println(numCells(Integer.parseInt(inputs.substring(0, 1)), 
                                                     Integer.parseInt(inputs.substring(2, 3)),
                                                     Integer.parseInt(inputs.substring(4, 5))));
    
    }
    
    public static int numCells(int a, int b, int t)	{
    	
    	double totCells = 1;
    	
    	while (t > 0)	{
    		totCells = 0.5 * a * totCells + 0.5 * b * totCells;
    		t--;
    	}
    	
    	totCells = totCells % (Math.pow(10, 9) + 7);
    	
    	
    	return (int) totCells;
    }
}