#include <bits/stdc++.h>
using namespace std;
#define _GLIBCXX_DEBUG
#define rep2(i, m, n) for(int i=int(m); i<int(n); ++i)
#define drep2(i, m, n) for(int i=int(m-1); i>=int(n); --i)
#define rep(i, n) rep2(i, 0, n)
#define drep(i, n) drep2(i, n, 0)
#define all(a) a.begin(), a.end()
using ll = long long;
using ld = long double;
using V = vector<int>;
using Vll = vector<ll>;
using Vld = vector<ld>;
using Vbo = vector<bool>;
using VV = vector<V>;
using VVll = vector<Vll>;
using VVld = vector<Vld>;
using VVbo = vector<Vbo>;
using P = pair<int, int>;
using Pll = pair<ll, ll>;
using Pld = pair<ld, ld>;
struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
template<typename T> inline bool chmin(T &a, T b) { if (a > b) { a = b; return true; } return false; }
template<typename T> inline bool chmax(T &a, T b) { if (a < b) { a = b; return true; } return false; }
template<typename T1, typename T2> istream &operator>>(istream &is, pair<T1, T2> &p) { is >> p.first >> p.second; return is; }
template<typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &p) { os << "(" << p.first << ", " << p.second << ")"; return os; }
template<typename T> istream &operator>>(istream &is, vector<T> &v) { for (auto &e : v) is >> e; return is; }
template<typename T> ostream &operator<<(ostream &os, const vector<T> &v) { for (auto &e : v) os << e << " "; return os; }
template<typename T> inline int count_between(vector<T> &a, T l, T r) { return lower_bound(all(a), r) - lower_bound(all(a), l); } // [l, r)
inline int Log2(ll x) { int k; for (k = 0; x > 0; ++k) x >>= 1; return k; } // number of binary digits
const int INF  = 1<<30;
const ll INFll = 1ll<<62;
const ld EPS   = 1e-10;
const int MOD  = int(1e9)+7;


struct mint {
  ll x;
  mint(ll x=0):x((x%MOD+MOD)%MOD){}
  mint operator-() const { return mint(-x);}
  mint& operator+=(const mint a) {
    if ((x += a.x) >= MOD) x -= MOD;
    return *this;
  }
  mint& operator-=(const mint a) {
    if ((x += MOD-a.x) >= MOD) x -= MOD;
    return *this;
  }
  mint& operator*=(const mint a) { (x *= a.x) %= MOD; return *this;}
  mint operator+(const mint a) const { return mint(*this) += a;}
  mint operator-(const mint a) const { return mint(*this) -= a;}
  mint operator*(const mint a) const { return mint(*this) *= a;}
  mint pow(ll t) const {
    if (!t) return 1;
    mint a = pow(t>>1);
    a *= a;
    if (t&1) a *= *this;
    return a;
  }
  mint& operator/=(const mint r) {
    ll a = r.x, b = MOD, u = 1, v = 0;
    while (b) {
      ll t = a / b;
      a -= t * b; swap(a, b);
      u -= t * v; swap(u, v);
    }
    x = x * u % MOD;
    if (x < 0) x += MOD;
    return *this;
  }
  mint operator/(const mint a) const { return mint(*this) /= a;}
};
istream& operator>>(istream& is, const mint& a) { return is >> a.x;}
ostream& operator<<(ostream& os, const mint& a) { return os << a.x;}


template<typename T>
struct SegmentTree {
private:
  int n, sz;
  vector<T> node;
public:
  SegmentTree(vector<T> v) : sz(v.size()) {
    n = 1; while(n < sz) n *= 2;
    node.resize(2*n-1, 0);
    for (int i=0; i<sz; i++) node[i+n-1] = v[i];
    for (int i=n-2; i>=0; i--) node[i] = node[i*2+1] + node[i*2+2];
  }

  void add(int k, T val) {
    k += (n - 1);
    node[k] += val;
    while (k > 0) {
      k = (k - 1) / 2;
      node[k] = node[2*k+1] + node[2*k+2];
    }
  }

  T sum(int a, int b, int k=0, int l=0, int r=-1) {
    if (r < 0) r = n;
    if (b <= l || r <= a) return 0;
    if (a <= l && r <= b) return node[k];
    T vl = sum(a, b, 2*k+1, l, (l+r)/2);
    T vr = sum(a, b, 2*k+2, (l+r)/2, r);
    return vl + vr;
  }

  T get(int a) {
    return sum(a, a+1);
  }

  vector<T> get_all() {
    vector<T> res(sz);
    copy(node.begin()+n-1, node.begin()+n+sz-1, res.begin());
    return res;
  }
};


int main() {
  ll n; cin >> n;

  SegmentTree<mint> st(vector<mint>(n+1));
  st.add(n, 1);
  st.add(n-1, n);

  mint a = n-1;
  a *= a;

  drep(i, n-1) {
    mint x = st.get(i+1);
    x += st.sum(i+3, n+1);
    x += i+1;
    x += a;
    st.add(i, x);
  }
  
  mint ans = st.get(0);
  cout << ans << endl;
  return 0;
}


Measured memory_bytes: 24448