#include using namespace std; using vi = vector; using vvi = vector; using vvvi = vector; using ll = long long int; using vll = vector; using vvll = vector; using vvvll = vector; using vd = vector; using vvd = vector; using vvvd = vector; using P = pair; using Pll = pair; using cdouble = complex; const double eps = 1e-9; const double INFD = numeric_limits::infinity(); const double PI = 3.14159265358979323846; #define Loop(i, n) for(int i = 0; i < (int)n; i++) #define Loopll(i, n) for(ll i = 0; i < (ll)n; i++) #define Loop1(i, n) for(int i = 1; i <= (int)n; i++) #define Loopll1(i, n) for(ll i = 1; i <= (ll)n; i++) #define Loopr(i, n) for(int i = (int)n - 1; i >= 0; i--) #define Looprll(i, n) for(ll i = (ll)n - 1; i >= 0; i--) #define Loopr1(i, n) for(int i = (int)n; i >= 1; i--) #define Looprll1(i, n) for(ll i = (ll)n; i >= 1; i--) #define Foreach(buf, container) for(auto buf : container) #define Loopdiag(i, j, h, w, sum) for(int i = ((sum) >= (h) ? (h) - 1 : (sum)), j = (sum) - i; i >= 0 && j < (w); i--, j++) #define Loopdiagr(i, j, h, w, sum) for(int j = ((sum) >= (w) ? (w) - 1 : (sum)), i = (sum) - j; j >= 0 && i < (h); j--, i++) #define Loopdiagsym(i, j, h, w, gap) for (int i = ((gap) >= 0 ? (gap) : 0), j = i - (gap); i < (h) && j < (w); i++, j++) #define Loopdiagsymr(i, j, h, w, gap) for (int i = ((gap) > (h) - (w) - 1 ? (h) - 1 : (w) - 1 + (gap)), j = i - (gap); i >= 0 && j >= 0; i--, j--) #define Loopitr(itr, container) for(auto itr = container.begin(); itr != container.end(); itr++) #define printv(vector) Loop(ex_i, vector.size()) { cout << vector[ex_i] << " "; } cout << endl; #define printmx(matrix) Loop(ex_i, matrix.size()) { Loop(ex_j, matrix[ex_i].size()) { cout << matrix[ex_i][ex_j] << " "; } cout << endl; } #define quickio() ios::sync_with_stdio(false); cin.tie(0); #define bitmanip(m,val) static_cast>(val) #define Comp(type_t) bool operator<(const type_t &another) const #define fst first #define snd second bool nearlyeq(double x, double y) { return abs(x - y) < eps; } bool inrange(int x, int t) { return x >= 0 && x < t; } bool inrange(vi xs, int t) { Foreach(x, xs) if (!(x >= 0 && x < t)) return false; return true; } ll rndf(double x) { return (ll)(x + (x >= 0 ? 0.5 : -0.5)); } ll floorsqrt(ll x) { ll m = (ll)sqrt((double)x); return m + (m * m <= x ? 0 : -1); } ll ceilsqrt(ll x) { ll m = (ll)sqrt((double)x); return m + (x <= m * m ? 0 : 1); } ll rnddiv(ll a, ll b) { return (a / b + (a % b * 2 >= b ? 1 : 0)); } ll ceildiv(ll a, ll b) { return (a / b + (a % b == 0 ? 0 : 1)); } ll gcd(ll m, ll n) { if (n == 0) return m; else return gcd(n, m % n); } ll lcm(ll m, ll n) { return m * n / gcd(m, n); } /*******************************************************/ namespace mod_op { const ll MOD = (ll)1e9 + 7; class modll { private: ll val; inline ll modify(ll x) { ll ret = x % MOD; if (ret < 0) ret += MOD; return ret; } inline ll inv(ll x) { if (x == 0) return 1 / x; else if (x == 1) return 1; else return modify(inv(MOD % x) * modify(-MOD / x)); } public: modll(ll init = 0) { val = modify(init); return; } modll(const modll& another) { val = another.val; return; } inline modll& operator=(const modll &another) { val = another.val; return *this; } inline modll operator+(const modll &x) { return modify(val + x.val); } inline modll operator-(const modll &x) { return modify(val - x.val); } inline modll operator*(const modll &x) { return modify(val * x.val); } inline modll operator/(const modll &x) { return modify(val * inv(x.val)); } inline modll& operator+=(const modll &x) { val = modify(val + x.val); return *this; } inline modll& operator-=(const modll &x) { val = modify(val - x.val); return *this; } inline modll& operator*=(const modll &x) { val = modify(val * x.val); return *this; } inline modll& operator/=(const modll &x) { val = modify(val * inv(x.val)); return *this; } inline bool operator==(const modll &x) { return val == x.val; } inline bool operator!=(const modll &x) { return val != x.val; } friend inline istream& operator >> (istream &is, modll& x) { is >> x.val; return is; } friend inline ostream& operator << (ostream &os, const modll& x) { os << x.val; return os; } ll get_val() { return val; } }; modll pow(modll n, ll p) { modll ret; if (p == 0) ret = 1; else if (p == 1) ret = n; else { ret = pow(n, p / 2); ret *= ret; if (p % 2 == 1) ret *= n; } return ret; } vector facts; inline void make_facts(int n) { if (facts.empty()) facts.push_back(modll(1)); for (int i = (int)facts.size(); i <= n; ++i) facts.push_back(modll(facts.back() * (ll)i)); return; } vector ifacts; vector invs; inline void make_invs(int n) { if (invs.empty()) { invs.push_back(modll(0)); invs.push_back(modll(1)); } for (int i = (int)invs.size(); i <= n; ++i) { // because 0 = MOD = kq + r, 1/k = -q/r invs.push_back(invs[(int)MOD % i] * ((int)MOD - (int)MOD / i)); } return; } inline void make_ifacts(int n) { make_invs(n); if (ifacts.empty()) ifacts.push_back(modll(1)); for (int i = (int)ifacts.size(); i <= n; ++i) ifacts.push_back(modll(ifacts.back() * invs[i])); return; } //nCr modll combination(ll n, ll r) { if (n >= r && r >= 0) { modll ret; make_facts((int)n); make_ifacts((int)n); ret = facts[(unsigned)n] * ifacts[(unsigned)r] * ifacts[(unsigned)(n - r)]; return ret; } else return 0; } modll get_fact(ll n) { make_facts((int)n); return facts[(int)n]; } modll get_ifact(ll n) { make_ifacts((int)n); return ifacts[(int)n]; } //log_a(b), if x does not exist, return -1 ll disc_log(modll a, modll b) { ll ret = -1; ll m = ceilsqrt(MOD); unordered_map mp; modll x = 1; Loop(i, m) { mp[x.get_val()] = i; x *= a; } x = modll(1) / pow(a, m); modll k = b; Loop(i, m) { if (mp.find(k.get_val()) == mp.end()) k *= x; else { ret = i * m + mp[k.get_val()]; break; } } return ret; } } using namespace mod_op; using vmodll = vector; using vvmodll = vector; using vvvmodll = vector; int main() { int n; cin >> n; modll ans = 0; Loop1(k, n) { ans += combination(n, k) * pow(modll(k), n - k); } cout << ans << endl; }