#!/bin/python

import sys

a, b, t = map(int,raw_input().strip().split(' '))

sum = 1
x = int((a*0.5) + (b*0.5))
y = 1

while t > 1:
    if t % 2 == 1:
        sum = (x * sum) % 1000000007
    x = (x * x) % 1000000007
    t = t / 2
    
sum = (x * sum) % 1000000007
   
print sum