N = int(input())
dp = [[0]*(3) for i in range(N+3)]
dp[1] = [1,0,0]
dp[2] = [0,1,0]
dp[3] = [1,1,1]
mod = 10**9+7

for i in range(4,N+3):
    dp[i][0] = (dp[i-1][1] + dp[i-1][2])%mod
    dp[i][1] = (dp[i-2][2] + dp[i-2][0])%mod
    dp[i][2] = (dp[i-3][0] + dp[i-3][1])%mod

print(sum(dp[N])%mod)