N=int(input())
dp=[[0]*3 for _ in range(N)]


dp[0][0]=1
for i in range(1,N):
  dp[i][0]=dp[i-1][2]
  dp[i][1]=dp[i-1][0]
  dp[i][2]=dp[i-1][0]+dp[i-1][1]
  dp[i][0]%=1000000007
  dp[i][1]%=1000000007
  dp[i][2]%=1000000007
print(sum(dp[N-1])%1000000007)