N=int(input())
dp=[[0]*3 for _ in range(N+1)]
dp[0][0],dp[0][1],dp[0][2]=0,1,0
for i in range(N):
    dp[i+1][0]+=dp[i][1]+dp[i][2]
    dp[i+1][1]+=dp[i][0]
    dp[i+1][2]+=dp[i][1]

sm=dp[N-1][0]+dp[N-1][1]+dp[N-1][2]
mod=10**9+7

print(sm%mod)