import sys; input = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)
from collections import defaultdict
con = 10 ** 9 + 7; INF = float("inf")

def getlist():
	return list(map(int, input().split()))

import numpy as np

def matrixPow(A, n, N, mod):
	B = np.identity(N, dtype = np.int)
	while n > 0:
		if n & 1 == 1:
			B = (A @ B) % mod
		A = (A @ A) % mod
		n >>= 1
	return B


#処理内容
def main():
	B, C, D = getlist()
	A = np.array([[C % con, B % con], [0, 1]])
	mat = matrixPow(A, D, 2, con)

	anspre = mat @ np.array([[B % con], [1]])
	ans = (anspre[0, 0] - B) % con
	print(ans)

if __name__ == '__main__':
	main()