MOD = 10 ** 9 + 7
a, b = map(int, input().split())
n = int(input())

def f(n):
    if n == 0:
        return 1, 0
    p, q = f(n // 2)
    p, q = (p * p + q * q * b) % MOD, 2 * p * q % MOD
    if n & 1:
        p, q = (a * p + 1 * q * b) % MOD, (a * q + 1 * p) % MOD
    return p, q
print(2 * f(n)[0] % MOD)