#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include<string.h>

int main(void)
{
	int a, b, time;
	scanf("%i%i%i", &a, &b, &time);
	double cells = 1;
	for( int i = 0; i < time; i++ )
	{
		cells = ((0.5 * a * cells) + (0.5 * b * cells));
	}
	cells = fmod(cells, (pow(10, 9) + 7));
	printf("%.0f\n", cells);
}