import sys

sys.setrecursionlimit(200005)
int1 = lambda x: int(x)-1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = 10**9
# md = 998244353
md = 10**9+7

from functools import lru_cache

@lru_cache(None)
def f(n):
    if n == 0: return 2
    if n == 1: return (2*a)%md
    if n%2: return (f(n-1)*2*a-(a**2-b)*f(n-2))%md
    return (f(n//2)**2%md-2*pow(a**2-b, n//2, md))%md

a, b = LI()
n = II()
print(f(n))