#include #include #include #include #include #include #include #include #include #include #include #include using namespace std; #define REP(i,n) for(int i=0;i<(int)(n);i++) #define RREP(i,n) for(int i=n-1;i>=0;i--) #define FOR(i,k,n) for(int i=(k);i<(int)(n);i++) #define all(i,n) (i),(i+n) int dx4[4]={1,0,-1,0}; int dy4[4]={0,-1,0,1}; int dx8[8]={1,0,-1,1,-1,1,0,-1}; int dy8[8]={1,1,1,0,0,-1,-1,-1}; typedef pair P; typedef pair SP; typedef long long ll; typedef pair PLL; const int INF = 1e9; const ll LLINF = 1e18; const int MAX_V = 1e6+1; const ll mod = 1000000007; // -------------------------------------- int n; int main() { cin.tie(0); ios::sync_with_stdio(false); cin >> n; ll dp[1000005][3] = {0}; dp[0][0] = 1; REP(i, n) { dp[i + 1][1] = (dp[i + 1][1] + dp[i][0]) % mod; dp[i + 1][2] = (dp[i + 1][2] + dp[i][1]) % mod; dp[i + 1][0] = (dp[i + 1][0] + dp[i][1]) % mod; dp[i + 1][0] = (dp[i][2] + dp[i + 1][0]) % mod; } ll ans = 0; REP(i, 3) { ans = (ans + dp[n][i]) % mod; } cout << ans << endl; }