import numpy as np


def mat_power(m: np.ndarray, n: int, mod: int) -> np.ndarray:
    if n == 0: return np.identity(len(m), dtype=object)
    res = mat_power(m, n // 2, mod)
    res = res @ res % mod
    if n % 2 == 1:
        res = res @ m % mod
    return res


MOD = 10 ** 9 + 7
B, C, D = map(int, input().split())

m = np.array(
    [[C, B],
     [0, 1]])
a = np.array(
    [[B],
     [1]])

t = mat_power(m, D, MOD) @ a
ans = (t[0, 0] - B) % MOD
print(ans)