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])