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()))

#処理内容
def main():
	N = int(input())
	DP = [[0, 0, 0] for i in range(N + 1)]
	DP[0][0] = 1

	for i in range(1, N + 1):
		DP[i][0] = (DP[i - 1][1] + DP[i - 1][2]) % con
		DP[i][1] = DP[i - 1][0] % con
		DP[i][2] = DP[i - 1][1] % con

	ans = sum(DP[-1]) % con
	print(ans)

if __name__ == '__main__':
	main()