# Enter your code here. Read input from STDIN. Print output to STDOUT
def po(x,y):
    if y == 0:
        return 1
    t = po(x,y/2)
    t = t%(10**9+7)
    
    if y%2 == 0:
        return (t*t)%(10**9+7)
    else:
        return (x*t*t)%(10**9+7)
a,b,n = map(int,raw_input().split())
p = int(0.5*(a+b))
print int(po(p,n))%(10**9+7)