#include<string> #include<deque> #include<queue> #include<vector> #include<algorithm> #include<iostream> #include<set> #include<cmath> #include<tuple> #include<map> #include<functional> using namespace std; typedef long long int llint; typedef bool izryt; #define mp make_pair #define mt make_tuple #define pub push_back #define puf push_front #define pob pop_back #define pof pop_front #define fir first #define sec second #define res resize #define ins insert #define era erase const int big=1e9; const int mod=1e9 + 7; int main(void){ int i,j,n,m;cin>>n; vector<llint>dp[3]; dp[0].res(n+10); dp[1].res(n+10); dp[2].res(n+10); dp[0][1]=1; dp[1][2]=1; dp[2][3]=1; for(i=0;i<n;i++){ dp[0][i+1]+=dp[1][i]+dp[2][i]; dp[1][i+2]+=dp[0][i]+dp[2][i]; dp[2][i+3]+=dp[0][i]+dp[1][i]; dp[0][i+1]%=mod; dp[1][i+2]%=mod; dp[2][i+3]%=mod; } cout<<(dp[0][n]+dp[1][n]+dp[2][n])%mod<<endl; return 0; }