#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define all(a) a.begin(),a.end() #define rep(i, n) for (ll i = 0; i < (n); i++) #define pb push_back #pragma GCC optimize("O3") #pragma GCC optimize("unroll-loops") using namespace std; typedef long long ll; typedef unsigned long long ull; typedef long double ld; typedef pair P; typedef complex com; constexpr int inf = 1000000010; constexpr ll INF = 1000000000000000010; constexpr ld eps = 1e-12; constexpr ld pi = 3.141592653589793238; template inline bool chmax(T &a, const U &b) { if (a < b) { a = b; return true; } return false; } template inline bool chmin(T &a, const U &b) { if (a > b) { a = b; return true; } return false; } vector> graph(1000010, vector()); vector cnt(1000010), sz(1000010, 1); void dfs(int n) { for (int i : graph[n]) { dfs(i); cnt[n] += cnt[i]; sz[n] += sz[i]; } cnt[n] += sz[n] - 1; } int main() { cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); int n; cin >> n; vector a(n); rep(i, n - 1) { int u, v; //cin >> u >> v; u = i + 1, v = i + 2; u--; v--; graph[u].pb(v); a[v] = true; } int root = -1; rep(i, n) if (!a[i]) root = i; dfs(root); ll ans = 0; rep(i, n) { ans += cnt[i]; ans %= 1000000007; } cout << ans << '\n'; }