N = int(input())
MOD = 10**9+7
dp = [[0]*(3) for _ in range(N+10)]
dp[0][0] = 1
for i in range(1, N+1):
    dp[i][0] = (dp[i-1][1] + dp[i-1][2])%MOD
    dp[i][1] = dp[i-1][0]
    dp[i][2] = dp[i-1][1]
print(sum(dp[N])%MOD)