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

def dot(aa, bb):
    h = len(aa)
    w = len(bb[0])
    res = [[0]*w for _ in range(h)]
    for i, row in enumerate(aa):
        for j, col in enumerate(zip(*bb)):
            v = 0
            # for a, b in zip(row, col): v += a*b
            # res[i][j] = v%md
            for a, b in zip(row, col): v += a*b%md
            res[i][j] = v%md
    return res

def matpow(mat, e):
    n = len(mat)
    res = [[1 if i == j else 0 for j in range(n)] for i in range(n)]
    while e:
        if e & 1: res = dot(res, mat)
        mat = dot(mat, mat)
        e >>= 1
    return res

a, b = LI()
s = (-a**2+b)%md
n = II()
if n==0:
    print(2)
    exit()

mat = [[2*a%md, 1],
       [s, 0]]

cc = matpow(mat, n-1)
ans = dot([[2*a, 2]], cc)
print(ans[0][0])