MOD = 10**9+7
N = int(input())

dp = [[0,0,0] for _ in range(N+1)]
dp[0][0] = 1
for i in range(N):
    dp[i+1][0] += dp[i][1] + dp[i][2]
    dp[i+1][0] %= MOD
    
    dp[i+1][1] += dp[i][0]
    dp[i+1][1] %= MOD

    dp[i+1][2] += dp[i][1]
    dp[i+1][2] %= MOD

print(sum(dp[-1]) % MOD)