#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; #define fst first #define scd second #define PB push_back #define MP make_pair #define all(a) a.begin(),a.end() #define rall(a) a.rbegin(),a.rend() #define omajinai ios::sync_with_stdio(false);cin.tie(0) #define rep(i,x) for(int i=0;i<(int)(x);++i) #define rep1(i,x) for(int i=1;i<=(int)(x);++i) #define rrep(i,x) for(int i=(int)x-1;i>=0;--i) #define rrep1(i,x) for(int i=(int)x;i>=1;--i) using ll=long long; using ld=long double; using vi=vector; using vvi=vector; using pii=pair; using vpii=vector; templateostream&operator<<(ostream&os,const pairp){os<<"("<ostream&operator<<(ostream&os,const vectorv){rep(i,v.size()){if(i)os<<", ";os<T&max(T&a,T&b){if(a>=b)return a;return b;} templateT&min(T&a,T&b){if(a < b)return a;return b;} templatebool chmax(T&a,T b){if(a < b){a=b;return true;}return false;} templatebool chmin(T&a,T b){if(a > b){a=b;return true;}return false;} constexpr int inf = 1e9; constexpr ll linf = 3e18; constexpr double eps = 1e-9; const int mod = 1e9 + 7; int dp[1000005][2][2]; // dp[何日目][今日][昨日] signed main() { int N; cin >> N; dp[0][0][1] = 1; for (int i = 0; i < N - 1; ++i) { for (int j = 0; j < 2; ++j) { for (int k = 0; k < 2; ++k) { for (int l = 0; l < 2; ++l) { if (j == 1 && k == 1) continue; if (k == 1 && l == 1) continue; if (j == 0 && j == k && k == l) continue; dp[i + 1][j][k] += dp[i][k][l]; dp[i + 1][j][k] %= mod; } } } } int sum = 0; rep(i, 2) { rep(j, 2) { if (i == 1 && j == 1) continue; sum += dp[N - 1][i][j]; sum %= mod; } } cout << sum << endl; }