MOD = 10**9 + 7
N = int(input())
# dp[i][0] パを選んだ時
# dp[i][1] ケンを選んだ時(1回目)
# dp[i][2] ケンを選んだ時(2回目)
dp = [[0]*3 for _ in range(N)]
dp[0][1] = 1
for i in range(1,N):
    dp[i][0] = (dp[i-1][1]+dp[i-1][2])%MOD
    dp[i][1] = dp[i-1][0]%MOD
    dp[i][2] = dp[i-1][1]%MOD
print(sum(dp[-1])%MOD)