#include<iostream> #include<vector> #include<algorithm> #include<iomanip> using namespace std; #define OVERLOAD_REP(_1, _2, _3, name, ...) name #define REP1(i, n) for (auto i = std::decay_t<decltype(n)>{}; (i) != (n); ++(i)) #define REP2(i, l, r) for (auto i = (l); (i) != (r); ++(i)) #define rep(...) OVERLOAD_REP(__VA_ARGS__, REP2, REP1)(__VA_ARGS__) #define REP(i, l, r) rep(i, l, r+1) #define all(x) (x).begin(),(x).end() #define inf 1000000000 using ll = long long; using P = pair<int,int>; using Graph = vector<vector<int> >; int main() { // 高速化 ios::sync_with_stdio(false); cin.tie(nullptr); // 小数点の出力桁数を指定 cout << fixed << setprecision(10); // メイン const ll mod = 1000000007; int N; cin >> N; vector<ll> dp(N + 5, 0); dp[0] = 1; for(int i = 0; i < N; i++) { dp[i] %= mod; dp[i + 2] += dp[i]; dp[i + 3] += dp[i]; if(N - i <= 2) dp[N] += dp[i]; } cout << dp[N] % mod << endl; return 0; }