def egcd(a, b):
    if a == 0:
        return (b, 0, 1)
    else:
        g, y, x = egcd(b % a, a)
        return (g, x - (b // a) * y, y)

def modinv(a, m):
    g, x, y = egcd(a, m)
    if g != 1:
        raise Exception('modular inverse does not exist')
    else:
        return x % m

def f(a, b, t, m):

    c2 = pow(a+b, t, m)
    c1 = pow(2, t, m)

    mi = modinv(c1, m)

    return (c2*mi) % m

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

print f(a, b, t, 10**9 + 7)