Problem p02666 (C++)

Buggy submission (status: Runtime Error):
#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES

#pragma comment(linker, "/STACK:526000000")

#include "bits/stdc++.h"
#define int ll

using namespace std;
typedef string::const_iterator State;
#define eps 1e-8L
#define MAX_MOD 1000000007LL
#define GYAKU 500000004LL
#define MOD 998244353LL
#define pb push_back
#define mp make_pair
typedef long long ll;
typedef long double ld;
#define REP(a, b) for (long long(a) = 0; (a) < (b); ++(a))
#define ALL(x) (x).begin(), (x).end()

int is_ok(int now) {
  int cnts[10] = {};
  while (now != 0) {
    cnts[now % 10]++;
    if (cnts[now % 10] == 2)
      return false;
    now /= 10;
  }
  return true;
}
int is_Prime(int now) {
  if (now == 1)
    return false;
  for (int i = 2; i * i <= now; ++i) {
    if (now % i == 0)
      return false;
  }
  return true;
}
class EllysDifferentPrimes {
public:
  static int getClosest(int n) {
    REP(q, 1e9) {
      if (n - q > 0 and is_ok(n - q) == 1 and is_Prime(n - q) == 1) {
        return n - q;
      }
      if (is_ok(n + q) == 1 and is_Prime(n + q) == 1) {
        return n + q;
      }
    }
    return -1;
  }
};

// geometry library

typedef complex<long double> Point;
typedef pair<complex<long double>, complex<long double>> Line;

typedef struct Circle {
  complex<long double> center;
  long double r;
} Circle;

long double dot(Point a, Point b) {
  return (a.real() * b.real() + a.imag() * b.imag());
}
long double cross(Point a, Point b) {
  return (a.real() * b.imag() - a.imag() * b.real());
}

long double Dist_Line_Point(Line a, Point b) {
  if (dot(a.second - a.first, b - a.first) < eps)
    return abs(b - a.first);
  if (dot(a.first - a.second, b - a.second) < eps)
    return abs(b - a.second);
  return abs(cross(a.second - a.first, b - a.first)) / abs(a.second - a.first);
}

int is_intersected_ls(Line a, Line b) {
  return (cross(a.second - a.first, b.first - a.first) *
              cross(a.second - a.first, b.second - a.first) <
          eps) &&
         (cross(b.second - b.first, a.first - b.first) *
              cross(b.second - b.first, a.second - b.first) <
          eps);
}

Point intersection_l(Line a, Line b) {
  Point da = a.second - a.first;
  Point db = b.second - b.first;
  return a.first + da * cross(db, b.first - a.first) / cross(db, da);
}

long double Dist_Line_Line(Line a, Line b) {
  if (is_intersected_ls(a, b) == 1) {
    return 0;
  }
  return min({Dist_Line_Point(a, b.first), Dist_Line_Point(a, b.second),
              Dist_Line_Point(b, a.first), Dist_Line_Point(b, a.second)});
}

pair<Point, Point> intersection_Circle_Circle(Circle a, Circle b) {
  long double dist = abs(a.center - b.center);
  assert(dist <= eps + a.r + b.r);
  assert(dist + eps >= abs(a.r - b.r));
  Point target = b.center - a.center;
  long double pointer =
      target.real() * target.real() + target.imag() * target.imag();
  long double aa = pointer + a.r * a.r - b.r * b.r;
  aa /= 2.0L;
  Point l{(aa * target.real() +
           target.imag() * sqrt(pointer * a.r * a.r - aa * aa)) /
              pointer,
          (aa * target.imag() -
           target.real() * sqrt(pointer * a.r * a.r - aa * aa)) /
              pointer};
  Point r{(aa * target.real() -
           target.imag() * sqrt(pointer * a.r * a.r - aa * aa)) /
              pointer,
          (aa * target.imag() +
           target.real() * sqrt(pointer * a.r * a.r - aa * aa)) /
              pointer};
  r = r + a.center;
  l = l + a.center;
  return mp(l, r);
}

// end of geometry

ll gcd(ll a, ll b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}

template <typename A> A pows(A val, ll b) {
  assert(b >= 1);
  A ans = val;
  b--;
  while (b) {
    if (b % 2) {
      ans *= val;
    }
    val *= val;
    b /= 2LL;
  }
  return ans;
}

template <typename A> class Compressor {
public:
  bool is_zipped = false;
  map<A, ll> zipper;
  map<ll, A> unzipper;
  queue<A> fetcher;
  Compressor() {
    is_zipped = false;
    zipper.clear();
    unzipper.clear();
  }
  void add(A now) {
    assert(is_zipped == false);
    zipper[now] = 1;
    fetcher.push(now);
  }
  void exec() {
    assert(is_zipped == false);
    int cnt = 0;
    for (auto i = zipper.begin(); i != zipper.end(); ++i) {
      i->second = cnt;
      unzipper[cnt] = i->first;
      cnt++;
    }
    is_zipped = true;
  }
  ll fetch() {
    assert(is_zipped == true);
    A hoge = fetcher.front();
    fetcher.pop();
    return zipper[hoge];
  }
  ll zip(A now) {
    assert(is_zipped == true);
    assert(zipper.find(now) != zipper.end());
    return zipper[now];
  }
  A unzip(ll a) {
    assert(is_zipped == true);
    assert(a < unzipper.size());
    return unzipper[a];
  }
  ll next(A now) {
    auto x = zipper.upper_bound(now);
    if (x == zipper.end())
      return zipper.size();
    return (ll)((*x).second);
  }
  ll back(A now) {
    auto x = zipper.lower_bound(now);
    if (x == zipper.begin())
      return -1;
    x--;
    return (ll)((*x).second);
  }
};

template <typename A> class Matrix {
public:
  vector<vector<A>> data;
  Matrix(vector<vector<A>> a) : data(a) {}
  Matrix operator+(const Matrix obj) {
    vector<vector<A>> ans;
    assert(obj.data.size() == this->data.size());
    assert(obj.data[0].size() == this->data[0].size());
    REP(i, obj.data.size()) {
      ans.push_back(vector<A>());
      REP(q, obj.data[i].size()) {
        A hoge = obj.data[i][q] + (this->data[i][q]);
        ans.back().push_back(hoge);
      }
    }
    return Matrix(ans);
  }
  Matrix operator-(const Matrix obj) {
    vector<vector<A>> ans;
    assert(obj.data.size() == this->data.size());
    assert(obj.data[0].size() == this->data[0].size());
    REP(i, obj.data.size()) {
      ans.push_back(vector<A>());
      REP(q, obj.data[i].size()) {
        A hoge = this->data[i][q] - obj.data[i][q];
        ans.back().push_back(hoge);
      }
    }
    return Matrix(ans);
  }
  Matrix operator*(const Matrix obj) {
    vector<vector<A>> ans;
    assert(obj.data.size() == this->data[0].size());
    REP(i, this->data.size()) {
      ans.push_back(vector<A>());
      REP(q, obj.data[0].size()) {
        A hoge = ((this->data[i][0]) * (obj.data[0][q]));
        for (int t = 1; t < obj.data.size(); ++t) {
          hoge += ((this->data[i][t]) * obj.data[t][q]);
        }
        ans.back().push_back(hoge);
      }
    }
    return Matrix(ans);
  }
  Matrix &operator*=(const Matrix obj) {
    *this = (*this * obj);
    return *this;
  }
  Matrix &operator+=(const Matrix obj) {
    *this = (*this + obj);
    return *this;
  }
  Matrix &operator-=(const Matrix obj) {
    *this = (*this - obj);
    return *this;
  }
};

struct Fraction {
  ll a;
  ll b;
  Fraction() : a(0LL), b(1LL) {}
  Fraction(ll c, ll d) {
    int hoge = gcd(llabs(c), llabs(d));
    c /= hoge;
    d /= hoge;
    if (d < 0) {
      d *= -1;
      c *= -1;
    }
    a = c;
    b = d;
  }
  bool operator<(Fraction rhs) const { return a * rhs.b < rhs.a * b; }
};

template <std::uint_fast64_t mod> class modint {
public:
  using u64 = std::uint_fast64_t;
  u64 value = 0;
  modint() : value(0LL) {}
  modint(ll a) : value(((a % mod) + 2 * mod) % mod) {}

  constexpr modint operator+(const modint rhs) const {
    return modint(*this) += rhs;
  }
  constexpr modint operator-(const modint rhs) const {
    return modint(*this) -= rhs;
  }
  constexpr modint operator*(const modint rhs) const {
    return modint(*this) *= rhs;
  }
  constexpr modint operator/(const modint rhs) const {
    return modint(*this) /= rhs;
  }
  constexpr modint &operator+=(const modint rhs) {
    value += rhs.value;
    if (value >= mod) {
      value -= mod;
    }
    return *this;
  }
  constexpr modint &operator-=(const modint rhs) {
    if (value < rhs.value) {
      value += mod;
    }
    value -= rhs.value;
    return *this;
  }
  constexpr modint &operator*=(const modint rhs) {
    value = (value * rhs.value) % mod;
    return *this;
  }
  constexpr modint &operator/=(modint rhs) {
    ll rem = mod - 2;
    while (rem) {
      if (rem % 2) {
        *this *= rhs;
      }
      rhs *= rhs;
      rem /= 2LL;
    }
    return *this;
  }
  bool operator<(modint rhs) const { return value < rhs.value; }
  friend ostream &operator<<(ostream &os, modint &p) {
    os << p.value;
    return (os);
  }
};

class Dice {
public:
  vector<ll> vertexs;
  // Up: 0,Left: 1,Center: 2,Right: 3,Adj: 4, Down: 5
  Dice(vector<ll> init) : vertexs(init) {}
  // Look from Center
  void RtoL() {
    for (int q = 1; q < 4; ++q) {
      swap(vertexs[q], vertexs[q + 1]);
    }
  }
  void LtoR() {
    for (int q = 3; q >= 1; --q) {
      swap(vertexs[q], vertexs[q + 1]);
    }
  }
  void UtoD() {
    swap(vertexs[5], vertexs[4]);
    swap(vertexs[2], vertexs[5]);
    swap(vertexs[0], vertexs[2]);
  }
  void DtoU() {
    swap(vertexs[0], vertexs[2]);
    swap(vertexs[2], vertexs[5]);
    swap(vertexs[5], vertexs[4]);
  }
  bool ReachAble(Dice now) {
    set<Dice> hoge;
    queue<Dice> next;
    next.push(now);
    hoge.insert(now);
    while (next.empty() == false) {
      Dice seeing = next.front();
      next.pop();
      if (seeing == *this)
        return true;
      seeing.RtoL();
      if (hoge.count(seeing) == 0) {
        hoge.insert(seeing);
        next.push(seeing);
      }
      seeing.LtoR();
      seeing.LtoR();
      if (hoge.count(seeing) == 0) {
        hoge.insert(seeing);
        next.push(seeing);
      }
      seeing.RtoL();
      seeing.UtoD();
      if (hoge.count(seeing) == 0) {
        hoge.insert(seeing);
        next.push(seeing);
      }
      seeing.DtoU();
      seeing.DtoU();
      if (hoge.count(seeing) == 0) {
        hoge.insert(seeing);
        next.push(seeing);
      }
    }
    return false;
  }
  bool operator==(const Dice &a) {
    for (int q = 0; q < 6; ++q) {
      if (a.vertexs[q] != (*this).vertexs[q]) {
        return false;
      }
    }
    return true;
  }
  bool operator<(const Dice &a) const { return (*this).vertexs < a.vertexs; }
};

pair<Dice, Dice> TwoDimDice(int center, int up) {
  int target = 1;
  while (true) {
    if (center != target && 7 - center != target && up != target &&
        7 - up != target) {
      break;
    }
    target++;
  }
  return mp(
      Dice(vector<ll>{up, target, center, 7 - target, 7 - center, 7 - up}),
      Dice(vector<ll>{up, 7 - target, center, target, 7 - center, 7 - up}));
}

tuple<Dice, Dice, Dice, Dice> OneDimDice(int center) {
  int bo = min(center, 7 - center);
  pair<int, int> goa;
  if (bo == 1) {
    goa = mp(2, 3);
  } else if (bo == 2) {
    goa = mp(1, 3);
  } else if (bo == 3) {
    goa = mp(1, 2);
  }
  tuple<Dice, Dice, Dice, Dice> now =
      make_tuple(Dice(vector<ll>{goa.first, goa.second, center, 7 - goa.second,
                                 7 - center, 7 - goa.first}),
                 Dice(vector<ll>{goa.first, 7 - goa.second, center, goa.second,
                                 7 - center, 7 - goa.first}),
                 Dice(vector<ll>{7 - goa.first, goa.second, center,
                                 7 - goa.second, 7 - center, goa.first}),
                 Dice(vector<ll>{7 - goa.first, 7 - goa.second, center,
                                 goa.second, 7 - center, goa.first}));
  return now;
}

template <typename A, typename B> class Dijkstra {
public:
  vector<vector<pair<int, A>>> vertexs;
  B Cost_Function;
  Dijkstra(int n, B cost) : Cost_Function(cost) {
    vertexs = vector<vector<pair<int, A>>>(n, vector<pair<int, A>>{});
  }
  ~Dijkstra() { vertexs.clear(); }
  void add_edge(int a, int b, A c) { vertexs[a].push_back(mp(b, c)); }
  vector<ll> build_result(int StartPoint) {
    vector<ll> dist(vertexs.size(), 2e18);
    dist[StartPoint] = 0;
    priority_queue<pair<ll, int>, vector<pair<ll, int>>, greater<pair<ll, int>>>
        next;
    next.push(make_pair(0, StartPoint));
    while (next.empty() == false) {
      pair<ll, int> now = next.top();
      next.pop();
      if (dist[now.second] != now.first)
        continue;
      for (auto x : vertexs[now.second]) {
        ll now_cost = now.first + Cost_Function(x.second);
        if (dist[x.first] > now_cost) {
          dist[x.first] = now_cost;
          next.push(mp(now_cost, x.first));
        }
      }
    }
    return dist;
  }
};

class Dinic {
public:
  struct edge {
    int to;
    int cap;
    int rev;
  };
  vector<vector<edge>> Graph;
  vector<int> level;
  vector<int> itr;
  Dinic(int n) { Graph = vector<vector<edge>>(n, vector<edge>()); }
  void add_edge(int a, int b, int cap) {
    Graph[a].push_back(edge{b, cap, (int)Graph[b].size()});
    Graph[b].push_back(edge{a, 0, (int)Graph[a].size() - 1});
  }
  void bfs(int s) {
    level = vector<int>(Graph.size(), -1);
    level[s] = 0;
    queue<int> next;
    next.push(s);
    while (next.empty() == false) {
      int now = next.front();
      next.pop();
      for (auto x : Graph[now]) {
        if (x.cap == 0)
          continue;
        if (level[x.to] == -1) {
          level[x.to] = level[now] + 1;
          next.push(x.to);
        }
      }
    }
  }
  int dfs(int now, int goal, int val) {
    if (goal == now)
      return val;
    for (int &i = itr[now]; i < (int)Graph[now].size(); ++i) {
      edge &target = Graph[now][i];
      if (target.cap > 0 && level[now] < level[target.to]) {
        int d = dfs(target.to, goal, min(val, target.cap));
        if (d > 0) {
          target.cap -= d;
          Graph[target.to][target.rev].cap += d;
          return d;
        }
      }
    }
    return 0;
  }
  int run(int s, int t) {
    int ans = 0;
    int f = 0;
    while (bfs(s), level[t] >= 0) {
      itr = vector<int>(Graph.size(), 0);
      while ((f = dfs(s, t, 1e9)) > 0) {
        ans += f;
      }
    }
    return ans;
  }
};

class HLDecomposition {
public:
  vector<vector<int>> vertexs;
  vector<int> depth;
  vector<int> backs;
  vector<int> connections;
  vector<int> zip, unzip;
  HLDecomposition(int n) {
    vertexs = vector<vector<int>>(n, vector<int>());
    depth = vector<int>(n);
    zip = vector<int>(n);
    unzip = zip;
  }
  void add_edge(int a, int b) {
    vertexs[a].push_back(b);
    vertexs[b].push_back(a);
  }
  int depth_dfs(int now, int back) {
    depth[now] = 0;
    for (auto x : vertexs[now]) {
      if (x == back)
        continue;
      depth[now] = max(depth[now], 1 + depth_dfs(x, now));
    }
    return depth[now];
  }
  void dfs(int now, int backing) {
    zip[now] = backs.size();
    unzip[backs.size()] = now;
    backs.push_back(backing);
    int now_max = -1;
    int itr = -1;
    for (auto x : vertexs[now]) {
      if (depth[x] > depth[now])
        continue;
      if (now_max < depth[x]) {
        now_max = depth[x];
        itr = x;
      }
    }
    if (itr == -1)
      return;
    connections.push_back(connections.back());
    dfs(itr, backing);
    for (auto x : vertexs[now]) {
      if (depth[x] > depth[now])
        continue;
      if (x == itr)
        continue;
      connections.push_back(zip[now]);
      dfs(x, backs.size());
    }
    return;
  }
  void build() {
    depth_dfs(0, -1);
    connections.push_back(-1);
    dfs(0, -1);
  }
  vector<pair<int, int>> query(int a, int b) {
    a = zip[a];
    b = zip[b];
    vector<pair<int, int>> ans;
    while (backs[a] != backs[b]) {
      if (a < b)
        swap(a, b);
      ans.push_back(mp(backs[a], a + 1));
      a = connections[a];
    }
    if (a > b)
      swap(a, b);
    ans.push_back(mp(a, b + 1));
    return ans;
  }
  int lca(int a, int b) {
    a = zip[a];
    b = zip[b];
    while (backs[a] != backs[b]) {
      if (a < b)
        swap(a, b);
      a = connections[a];
    }
    return unzip[min(a, b)];
  }
};
// by ei1333
// https://ei1333.github.io/luzhiled/snippets/structure/segment-tree.html
template <typename Monoid> struct SegmentTree {
  using F = function<Monoid(Monoid, Monoid)>;

  int sz;
  vector<Monoid> seg;

  const F f;
  const Monoid M1;

  SegmentTree(int n, const F f, const Monoid &M1) : f(f), M1(M1) {
    sz = 1;
    while (sz < n)
      sz <<= 1;
    seg.assign(2 * sz + 1, M1);
  }

  void set(int k, const Monoid &x) { seg[k + sz] = x; }

  void build() {
    for (int k = sz - 1; k > 0; k--) {
      seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]);
    }
  }

  void update(int k, const Monoid &x) {
    k += sz;
    seg[k] = x;
    while (k >>= 1) {
      seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]);
    }
  }

  Monoid query(int a, int b) {
    Monoid L = M1, R = M1;
    for (a += sz, b += sz; a < b; a >>= 1, b >>= 1) {
      if (a & 1)
        L = f(L, seg[a++]);
      if (b & 1)
        R = f(seg[--b], R);
    }
    return f(L, R);
  }

  Monoid operator[](const int &k) const { return seg[k + sz]; }

  template <typename C>
  int find_subtree(int a, const C &check, Monoid &M, bool type) {
    while (a < sz) {
      Monoid nxt = type ? f(seg[2 * a + type], M) : f(M, seg[2 * a + type]);
      if (check(nxt))
        a = 2 * a + type;
      else
        M = nxt, a = 2 * a + 1 - type;
    }
    return a - sz;
  }

  template <typename C> int find_first(int a, const C &check) {
    Monoid L = M1;
    if (a <= 0) {
      if (check(f(L, seg[1])))
        return find_subtree(1, check, L, false);
      return -1;
    }
    int b = sz;
    for (a += sz, b += sz; a < b; a >>= 1, b >>= 1) {
      if (a & 1) {
        Monoid nxt = f(L, seg[a]);
        if (check(nxt))
          return find_subtree(a, check, L, false);
        L = nxt;
        ++a;
      }
    }
    return -1;
  }

  template <typename C> int find_last(int b, const C &check) {
    Monoid R = M1;
    if (b >= sz) {
      if (check(f(seg[1], R)))
        return find_subtree(1, check, R, true);
      return -1;
    }
    int a = sz;
    for (b += sz; a < b; a >>= 1, b >>= 1) {
      if (b & 1) {
        Monoid nxt = f(seg[--b], R);
        if (check(nxt))
          return find_subtree(b, check, R, true);
        R = nxt;
      }
    }
    return -1;
  }
};

template <typename Monoid, typename OperatorMonoid = Monoid>
struct LazySegmentTree {
  using F = function<Monoid(Monoid, Monoid)>;
  using G = function<Monoid(Monoid, OperatorMonoid)>;
  using H = function<OperatorMonoid(OperatorMonoid, OperatorMonoid)>;

  int sz, height;
  vector<Monoid> data;
  vector<OperatorMonoid> lazy;
  const F f;
  const G g;
  const H h;
  const Monoid M1;
  const OperatorMonoid OM0;

  LazySegmentTree(int n, const F f, const G g, const H h, const Monoid &M1,
                  const OperatorMonoid OM0)
      : f(f), g(g), h(h), M1(M1), OM0(OM0) {
    sz = 1;
    height = 0;
    while (sz < n)
      sz <<= 1, height++;
    data.assign(2 * sz, M1);
    lazy.assign(2 * sz, OM0);
  }

  void set(int k, const Monoid &x) { data[k + sz] = x; }

  void build() {
    for (int k = sz - 1; k > 0; k--) {
      data[k] = f(data[2 * k + 0], data[2 * k + 1]);
    }
  }

  inline void propagate(int k) {
    if (lazy[k] != OM0) {
      lazy[2 * k + 0] = h(lazy[2 * k + 0], lazy[k]);
      lazy[2 * k + 1] = h(lazy[2 * k + 1], lazy[k]);
      data[k] = reflect(k);
      lazy[k] = OM0;
    }
  }

  inline Monoid reflect(int k) {
    return lazy[k] == OM0 ? data[k] : g(data[k], lazy[k]);
  }

  inline void recalc(int k) {
    while (k >>= 1)
      data[k] = f(reflect(2 * k + 0), reflect(2 * k + 1));
  }

  inline void thrust(int k) {
    for (int i = height; i > 0; i--)
      propagate(k >> i);
  }

  void update(int a, int b, const OperatorMonoid &x) {
    thrust(a += sz);
    thrust(b += sz - 1);
    for (int l = a, r = b + 1; l < r; l >>= 1, r >>= 1) {
      if (l & 1)
        lazy[l] = h(lazy[l], x), ++l;
      if (r & 1)
        --r, lazy[r] = h(lazy[r], x);
    }
    recalc(a);
    recalc(b);
  }

  Monoid query(int a, int b) {
    thrust(a += sz);
    thrust(b += sz - 1);
    Monoid L = M1, R = M1;
    for (int l = a, r = b + 1; l < r; l >>= 1, r >>= 1) {
      if (l & 1)
        L = f(L, reflect(l++));
      if (r & 1)
        R = f(reflect(--r), R);
    }
    return f(L, R);
  }

  Monoid operator[](const int &k) { return query(k, k + 1); }

  template <typename C>
  int find_subtree(int a, const C &check, Monoid &M, bool type) {
    while (a < sz) {
      propagate(a);
      Monoid nxt =
          type ? f(reflect(2 * a + type), M) : f(M, reflect(2 * a + type));
      if (check(nxt))
        a = 2 * a + type;
      else
        M = nxt, a = 2 * a + 1 - type;
    }
    return a - sz;
  }

  template <typename C> int find_first(int a, const C &check) {
    Monoid L = M1;
    if (a <= 0) {
      if (check(f(L, reflect(1))))
        return find_subtree(1, check, L, false);
      return -1;
    }
    thrust(a + sz);
    int b = sz;
    for (a += sz, b += sz; a < b; a >>= 1, b >>= 1) {
      if (a & 1) {
        Monoid nxt = f(L, reflect(a));
        if (check(nxt))
          return find_subtree(a, check, L, false);
        L = nxt;
        ++a;
      }
    }
    return -1;
  }

  template <typename C> int find_last(int b, const C &check) {
    Monoid R = M1;
    if (b >= sz) {
      if (check(f(reflect(1), R)))
        return find_subtree(1, check, R, true);
      return -1;
    }
    thrust(b + sz - 1);
    int a = sz;
    for (b += sz; a < b; a >>= 1, b >>= 1) {
      if (b & 1) {
        Monoid nxt = f(reflect(--b), R);
        if (check(nxt))
          return find_subtree(b, check, R, true);
        R = nxt;
      }
    }
    return -1;
  }
};

class KMP {
public:
  vector<ll> table;
  vector<ll> Pattern;
  KMP(vector<ll> a) { build(a); }
  void build(vector<ll> a) {
    Pattern = a;
    table = vector<ll>(a.size() + 1, -1);
    int j = -1;
    for (int i = 0; i < a.size(); ++i) {
      while (j >= 0 && Pattern[i] != Pattern[j]) {
        j = table[j];
      }
      table[i + 1] = ++j;
    }
    return;
  }
  vector<ll> search(vector<ll> a) {
    vector<ll> ans;
    for (int i = 0, k = 0; i < a.size(); ++i) {
      while (k >= 0 && a[i] != Pattern[k])
        k = table[k];
      ++k;
      if (k >= Pattern.size()) {
        ans.push_back(i - Pattern.size() + 1);
        k = table[k];
      }
    }
    return ans;
  }
};

unsigned long xor128() {
  static unsigned long x = 123456789, y = 362436069, z = 521288629,
                       w = 88675123;
  unsigned long t = (x ^ (x << 11));
  x = y;
  y = z;
  z = w;
  return (w = (w ^ (w >> 19)) ^ (t ^ (t >> 8)));
}

void init() {
  iostream::sync_with_stdio(false);
  cout << fixed << setprecision(20);
}

#define int ll

template <typename flow_t, typename cost_t> struct PrimalDual {
  const cost_t INF;

  struct edge {
    int to;
    flow_t cap;
    cost_t cost;
    int rev;
    bool isrev;
  };
  vector<vector<edge>> graph;
  vector<cost_t> potential, min_cost;
  vector<int> prevv, preve;

  PrimalDual(int V) : graph(V), INF(numeric_limits<cost_t>::max()) {}

  void add_edge(int from, int to, flow_t cap, cost_t cost) {
    graph[from].emplace_back(edge{to, cap, cost, (int)graph[to].size(), false});
    graph[to].emplace_back(
        edge{from, 0, -cost, (int)graph[from].size() - 1, true});
  }

  cost_t min_cost_flow(int s, int t, flow_t f) {
    int V = (int)graph.size();
    cost_t ret = 0;
    using Pi = pair<cost_t, int>;
    priority_queue<Pi, vector<Pi>, greater<Pi>> que;
    potential.assign(V, 0);
    preve.assign(V, -1);
    prevv.assign(V, -1);

    while (f > 0) {
      min_cost.assign(V, INF);
      que.emplace(0, s);
      min_cost[s] = 0;
      while (!que.empty()) {
        Pi p = que.top();
        que.pop();
        if (min_cost[p.second] < p.first)
          continue;
        for (int i = 0; i < graph[p.second].size(); i++) {
          edge &e = graph[p.second][i];
          cost_t nextCost = min_cost[p.second] + e.cost + potential[p.second] -
                            potential[e.to];
          if (e.cap > 0 && min_cost[e.to] > nextCost) {
            min_cost[e.to] = nextCost;
            prevv[e.to] = p.second, preve[e.to] = i;
            que.emplace(min_cost[e.to], e.to);
          }
        }
      }
      if (min_cost[t] == INF)
        return -1;
      for (int v = 0; v < V; v++)
        potential[v] += min_cost[v];
      flow_t addflow = f;
      for (int v = t; v != s; v = prevv[v]) {
        addflow = min(addflow, graph[prevv[v]][preve[v]].cap);
      }
      f -= addflow;
      ret += addflow * potential[t];
      for (int v = t; v != s; v = prevv[v]) {
        edge &e = graph[prevv[v]][preve[v]];
        e.cap -= addflow;
        graph[v][e.rev].cap += addflow;
      }
    }
    return ret;
  }

  void output() {
    for (int i = 0; i < graph.size(); i++) {
      for (auto &e : graph[i]) {
        if (e.isrev)
          continue;
        auto &rev_e = graph[e.to][e.rev];
        cout << i << "->" << e.to << " (flow: " << rev_e.cap << "/"
             << rev_e.cap + e.cap << ")" << endl;
      }
    }
  }
};

// base64 エンコード
bool encode_base64(const std::vector<unsigned char> &src, std::string &dst) {
  const std::string table(
      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/");
  std::string cdst;

  for (std::size_t i = 0; i < src.size(); ++i) {
    switch (i % 3) {
    case 0:
      cdst.push_back(table[(src[i] & 0xFC) >> 2]);
      if (i + 1 == src.size()) {
        cdst.push_back(table[(src[i] & 0x03) << 4]);
        cdst.push_back('=');
        cdst.push_back('=');
      }

      break;
    case 1:
      cdst.push_back(
          table[((src[i - 1] & 0x03) << 4) | ((src[i + 0] & 0xF0) >> 4)]);
      if (i + 1 == src.size()) {
        cdst.push_back(table[(src[i] & 0x0F) << 2]);
        cdst.push_back('=');
      }

      break;
    case 2:
      cdst.push_back(
          table[((src[i - 1] & 0x0F) << 2) | ((src[i + 0] & 0xC0) >> 6)]);
      cdst.push_back(table[src[i] & 0x3F]);

      break;
    }
  }

  dst.swap(cdst);

  return true;
}

int ut[30000];
int uf(int now) {
  if (now == ut[now])
    return now;
  return ut[now] = uf(ut[now]);
}
int um(int a, int b) {
  a = uf(a);
  b = uf(b);
  if (a == b)
    return 0;
  ut[a] = b;
  return 1;
}

int cnter[30000];

modint<MAX_MOD> dp[6000];
void solve() {
  int n;
  cin >> n;
  vector<int> inputs;
  REP(i, n) {
    int a;
    cin >> a;
    a--;
    a = max(a, -1LL);
    inputs.push_back(a);
    ut[i] = i;
  }
  int base_cnt = 0;
  REP(i, n) {
    if (inputs[i] == -1)
      continue;
    base_cnt += 1 - um(i, inputs[i]);
  }
  REP(i, n) { cnter[uf(i)]++; }
  vector<int> Finds;
  REP(i, n) {
    if (inputs[i] == -1) {
      Finds.push_back(cnter[uf(i)]);
    }
  }
  REP(i, Finds.size()) {
    for (int q = i; q >= 0; --q) {
      dp[q + 1] += dp[q] * Finds[i];
    }
    dp[0] += Finds[i];
  }
  modint<MAX_MOD> ans =
      pows<modint<MAX_MOD>>(n - 1, Finds.size()) * (n - base_cnt);
  modint<MAX_MOD> gekos = 1;
  dp[0] -= Finds.size();
  for (int i = 0; i < Finds.size(); ++i) {
    modint<MAX_MOD> hoge = dp[i] * gekos;
    if (Finds.size() - i - 1 != 0) {
      hoge *= pows<modint<MAX_MOD>>(n - 1, Finds.size() - i - 1);
    }
    ans -= hoge;
    gekos *= (i + 1);
  }
  cout << ans << endl;
}
#undef int
int main() {
  init();
  solve();
}


Fixed submission:
#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES

#pragma comment(linker, "/STACK:526000000")

#include "bits/stdc++.h"
#define int ll

using namespace std;
typedef string::const_iterator State;
#define eps 1e-8L
#define MAX_MOD 1000000007LL
#define GYAKU 500000004LL
#define MOD 998244353LL
#define pb push_back
#define mp make_pair
typedef long long ll;
typedef long double ld;
#define REP(a, b) for (long long(a) = 0; (a) < (b); ++(a))
#define ALL(x) (x).begin(), (x).end()

int is_ok(int now) {
  int cnts[10] = {};
  while (now != 0) {
    cnts[now % 10]++;
    if (cnts[now % 10] == 2)
      return false;
    now /= 10;
  }
  return true;
}
int is_Prime(int now) {
  if (now == 1)
    return false;
  for (int i = 2; i * i <= now; ++i) {
    if (now % i == 0)
      return false;
  }
  return true;
}
class EllysDifferentPrimes {
public:
  static int getClosest(int n) {
    REP(q, 1e9) {
      if (n - q > 0 and is_ok(n - q) == 1 and is_Prime(n - q) == 1) {
        return n - q;
      }
      if (is_ok(n + q) == 1 and is_Prime(n + q) == 1) {
        return n + q;
      }
    }
    return -1;
  }
};

// geometry library

typedef complex<long double> Point;
typedef pair<complex<long double>, complex<long double>> Line;

typedef struct Circle {
  complex<long double> center;
  long double r;
} Circle;

long double dot(Point a, Point b) {
  return (a.real() * b.real() + a.imag() * b.imag());
}
long double cross(Point a, Point b) {
  return (a.real() * b.imag() - a.imag() * b.real());
}

long double Dist_Line_Point(Line a, Point b) {
  if (dot(a.second - a.first, b - a.first) < eps)
    return abs(b - a.first);
  if (dot(a.first - a.second, b - a.second) < eps)
    return abs(b - a.second);
  return abs(cross(a.second - a.first, b - a.first)) / abs(a.second - a.first);
}

int is_intersected_ls(Line a, Line b) {
  return (cross(a.second - a.first, b.first - a.first) *
              cross(a.second - a.first, b.second - a.first) <
          eps) &&
         (cross(b.second - b.first, a.first - b.first) *
              cross(b.second - b.first, a.second - b.first) <
          eps);
}

Point intersection_l(Line a, Line b) {
  Point da = a.second - a.first;
  Point db = b.second - b.first;
  return a.first + da * cross(db, b.first - a.first) / cross(db, da);
}

long double Dist_Line_Line(Line a, Line b) {
  if (is_intersected_ls(a, b) == 1) {
    return 0;
  }
  return min({Dist_Line_Point(a, b.first), Dist_Line_Point(a, b.second),
              Dist_Line_Point(b, a.first), Dist_Line_Point(b, a.second)});
}

pair<Point, Point> intersection_Circle_Circle(Circle a, Circle b) {
  long double dist = abs(a.center - b.center);
  assert(dist <= eps + a.r + b.r);
  assert(dist + eps >= abs(a.r - b.r));
  Point target = b.center - a.center;
  long double pointer =
      target.real() * target.real() + target.imag() * target.imag();
  long double aa = pointer + a.r * a.r - b.r * b.r;
  aa /= 2.0L;
  Point l{(aa * target.real() +
           target.imag() * sqrt(pointer * a.r * a.r - aa * aa)) /
              pointer,
          (aa * target.imag() -
           target.real() * sqrt(pointer * a.r * a.r - aa * aa)) /
              pointer};
  Point r{(aa * target.real() -
           target.imag() * sqrt(pointer * a.r * a.r - aa * aa)) /
              pointer,
          (aa * target.imag() +
           target.real() * sqrt(pointer * a.r * a.r - aa * aa)) /
              pointer};
  r = r + a.center;
  l = l + a.center;
  return mp(l, r);
}

// end of geometry

ll gcd(ll a, ll b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}

template <typename A> A pows(A val, ll b) {
  assert(b >= 1);
  A ans = val;
  b--;
  while (b) {
    if (b % 2) {
      ans *= val;
    }
    val *= val;
    b /= 2LL;
  }
  return ans;
}

template <typename A> class Compressor {
public:
  bool is_zipped = false;
  map<A, ll> zipper;
  map<ll, A> unzipper;
  queue<A> fetcher;
  Compressor() {
    is_zipped = false;
    zipper.clear();
    unzipper.clear();
  }
  void add(A now) {
    assert(is_zipped == false);
    zipper[now] = 1;
    fetcher.push(now);
  }
  void exec() {
    assert(is_zipped == false);
    int cnt = 0;
    for (auto i = zipper.begin(); i != zipper.end(); ++i) {
      i->second = cnt;
      unzipper[cnt] = i->first;
      cnt++;
    }
    is_zipped = true;
  }
  ll fetch() {
    assert(is_zipped == true);
    A hoge = fetcher.front();
    fetcher.pop();
    return zipper[hoge];
  }
  ll zip(A now) {
    assert(is_zipped == true);
    assert(zipper.find(now) != zipper.end());
    return zipper[now];
  }
  A unzip(ll a) {
    assert(is_zipped == true);
    assert(a < unzipper.size());
    return unzipper[a];
  }
  ll next(A now) {
    auto x = zipper.upper_bound(now);
    if (x == zipper.end())
      return zipper.size();
    return (ll)((*x).second);
  }
  ll back(A now) {
    auto x = zipper.lower_bound(now);
    if (x == zipper.begin())
      return -1;
    x--;
    return (ll)((*x).second);
  }
};

template <typename A> class Matrix {
public:
  vector<vector<A>> data;
  Matrix(vector<vector<A>> a) : data(a) {}
  Matrix operator+(const Matrix obj) {
    vector<vector<A>> ans;
    assert(obj.data.size() == this->data.size());
    assert(obj.data[0].size() == this->data[0].size());
    REP(i, obj.data.size()) {
      ans.push_back(vector<A>());
      REP(q, obj.data[i].size()) {
        A hoge = obj.data[i][q] + (this->data[i][q]);
        ans.back().push_back(hoge);
      }
    }
    return Matrix(ans);
  }
  Matrix operator-(const Matrix obj) {
    vector<vector<A>> ans;
    assert(obj.data.size() == this->data.size());
    assert(obj.data[0].size() == this->data[0].size());
    REP(i, obj.data.size()) {
      ans.push_back(vector<A>());
      REP(q, obj.data[i].size()) {
        A hoge = this->data[i][q] - obj.data[i][q];
        ans.back().push_back(hoge);
      }
    }
    return Matrix(ans);
  }
  Matrix operator*(const Matrix obj) {
    vector<vector<A>> ans;
    assert(obj.data.size() == this->data[0].size());
    REP(i, this->data.size()) {
      ans.push_back(vector<A>());
      REP(q, obj.data[0].size()) {
        A hoge = ((this->data[i][0]) * (obj.data[0][q]));
        for (int t = 1; t < obj.data.size(); ++t) {
          hoge += ((this->data[i][t]) * obj.data[t][q]);
        }
        ans.back().push_back(hoge);
      }
    }
    return Matrix(ans);
  }
  Matrix &operator*=(const Matrix obj) {
    *this = (*this * obj);
    return *this;
  }
  Matrix &operator+=(const Matrix obj) {
    *this = (*this + obj);
    return *this;
  }
  Matrix &operator-=(const Matrix obj) {
    *this = (*this - obj);
    return *this;
  }
};

struct Fraction {
  ll a;
  ll b;
  Fraction() : a(0LL), b(1LL) {}
  Fraction(ll c, ll d) {
    int hoge = gcd(llabs(c), llabs(d));
    c /= hoge;
    d /= hoge;
    if (d < 0) {
      d *= -1;
      c *= -1;
    }
    a = c;
    b = d;
  }
  bool operator<(Fraction rhs) const { return a * rhs.b < rhs.a * b; }
};

template <std::uint_fast64_t mod> class modint {
public:
  using u64 = std::uint_fast64_t;
  u64 value = 0;
  modint() : value(0LL) {}
  modint(ll a) : value(((a % mod) + 2 * mod) % mod) {}

  constexpr modint operator+(const modint rhs) const {
    return modint(*this) += rhs;
  }
  constexpr modint operator-(const modint rhs) const {
    return modint(*this) -= rhs;
  }
  constexpr modint operator*(const modint rhs) const {
    return modint(*this) *= rhs;
  }
  constexpr modint operator/(const modint rhs) const {
    return modint(*this) /= rhs;
  }
  constexpr modint &operator+=(const modint rhs) {
    value += rhs.value;
    if (value >= mod) {
      value -= mod;
    }
    return *this;
  }
  constexpr modint &operator-=(const modint rhs) {
    if (value < rhs.value) {
      value += mod;
    }
    value -= rhs.value;
    return *this;
  }
  constexpr modint &operator*=(const modint rhs) {
    value = (value * rhs.value) % mod;
    return *this;
  }
  constexpr modint &operator/=(modint rhs) {
    ll rem = mod - 2;
    while (rem) {
      if (rem % 2) {
        *this *= rhs;
      }
      rhs *= rhs;
      rem /= 2LL;
    }
    return *this;
  }
  bool operator<(modint rhs) const { return value < rhs.value; }
  friend ostream &operator<<(ostream &os, modint &p) {
    os << p.value;
    return (os);
  }
};

class Dice {
public:
  vector<ll> vertexs;
  // Up: 0,Left: 1,Center: 2,Right: 3,Adj: 4, Down: 5
  Dice(vector<ll> init) : vertexs(init) {}
  // Look from Center
  void RtoL() {
    for (int q = 1; q < 4; ++q) {
      swap(vertexs[q], vertexs[q + 1]);
    }
  }
  void LtoR() {
    for (int q = 3; q >= 1; --q) {
      swap(vertexs[q], vertexs[q + 1]);
    }
  }
  void UtoD() {
    swap(vertexs[5], vertexs[4]);
    swap(vertexs[2], vertexs[5]);
    swap(vertexs[0], vertexs[2]);
  }
  void DtoU() {
    swap(vertexs[0], vertexs[2]);
    swap(vertexs[2], vertexs[5]);
    swap(vertexs[5], vertexs[4]);
  }
  bool ReachAble(Dice now) {
    set<Dice> hoge;
    queue<Dice> next;
    next.push(now);
    hoge.insert(now);
    while (next.empty() == false) {
      Dice seeing = next.front();
      next.pop();
      if (seeing == *this)
        return true;
      seeing.RtoL();
      if (hoge.count(seeing) == 0) {
        hoge.insert(seeing);
        next.push(seeing);
      }
      seeing.LtoR();
      seeing.LtoR();
      if (hoge.count(seeing) == 0) {
        hoge.insert(seeing);
        next.push(seeing);
      }
      seeing.RtoL();
      seeing.UtoD();
      if (hoge.count(seeing) == 0) {
        hoge.insert(seeing);
        next.push(seeing);
      }
      seeing.DtoU();
      seeing.DtoU();
      if (hoge.count(seeing) == 0) {
        hoge.insert(seeing);
        next.push(seeing);
      }
    }
    return false;
  }
  bool operator==(const Dice &a) {
    for (int q = 0; q < 6; ++q) {
      if (a.vertexs[q] != (*this).vertexs[q]) {
        return false;
      }
    }
    return true;
  }
  bool operator<(const Dice &a) const { return (*this).vertexs < a.vertexs; }
};

pair<Dice, Dice> TwoDimDice(int center, int up) {
  int target = 1;
  while (true) {
    if (center != target && 7 - center != target && up != target &&
        7 - up != target) {
      break;
    }
    target++;
  }
  return mp(
      Dice(vector<ll>{up, target, center, 7 - target, 7 - center, 7 - up}),
      Dice(vector<ll>{up, 7 - target, center, target, 7 - center, 7 - up}));
}

tuple<Dice, Dice, Dice, Dice> OneDimDice(int center) {
  int bo = min(center, 7 - center);
  pair<int, int> goa;
  if (bo == 1) {
    goa = mp(2, 3);
  } else if (bo == 2) {
    goa = mp(1, 3);
  } else if (bo == 3) {
    goa = mp(1, 2);
  }
  tuple<Dice, Dice, Dice, Dice> now =
      make_tuple(Dice(vector<ll>{goa.first, goa.second, center, 7 - goa.second,
                                 7 - center, 7 - goa.first}),
                 Dice(vector<ll>{goa.first, 7 - goa.second, center, goa.second,
                                 7 - center, 7 - goa.first}),
                 Dice(vector<ll>{7 - goa.first, goa.second, center,
                                 7 - goa.second, 7 - center, goa.first}),
                 Dice(vector<ll>{7 - goa.first, 7 - goa.second, center,
                                 goa.second, 7 - center, goa.first}));
  return now;
}

template <typename A, typename B> class Dijkstra {
public:
  vector<vector<pair<int, A>>> vertexs;
  B Cost_Function;
  Dijkstra(int n, B cost) : Cost_Function(cost) {
    vertexs = vector<vector<pair<int, A>>>(n, vector<pair<int, A>>{});
  }
  ~Dijkstra() { vertexs.clear(); }
  void add_edge(int a, int b, A c) { vertexs[a].push_back(mp(b, c)); }
  vector<ll> build_result(int StartPoint) {
    vector<ll> dist(vertexs.size(), 2e18);
    dist[StartPoint] = 0;
    priority_queue<pair<ll, int>, vector<pair<ll, int>>, greater<pair<ll, int>>>
        next;
    next.push(make_pair(0, StartPoint));
    while (next.empty() == false) {
      pair<ll, int> now = next.top();
      next.pop();
      if (dist[now.second] != now.first)
        continue;
      for (auto x : vertexs[now.second]) {
        ll now_cost = now.first + Cost_Function(x.second);
        if (dist[x.first] > now_cost) {
          dist[x.first] = now_cost;
          next.push(mp(now_cost, x.first));
        }
      }
    }
    return dist;
  }
};

class Dinic {
public:
  struct edge {
    int to;
    int cap;
    int rev;
  };
  vector<vector<edge>> Graph;
  vector<int> level;
  vector<int> itr;
  Dinic(int n) { Graph = vector<vector<edge>>(n, vector<edge>()); }
  void add_edge(int a, int b, int cap) {
    Graph[a].push_back(edge{b, cap, (int)Graph[b].size()});
    Graph[b].push_back(edge{a, 0, (int)Graph[a].size() - 1});
  }
  void bfs(int s) {
    level = vector<int>(Graph.size(), -1);
    level[s] = 0;
    queue<int> next;
    next.push(s);
    while (next.empty() == false) {
      int now = next.front();
      next.pop();
      for (auto x : Graph[now]) {
        if (x.cap == 0)
          continue;
        if (level[x.to] == -1) {
          level[x.to] = level[now] + 1;
          next.push(x.to);
        }
      }
    }
  }
  int dfs(int now, int goal, int val) {
    if (goal == now)
      return val;
    for (int &i = itr[now]; i < (int)Graph[now].size(); ++i) {
      edge &target = Graph[now][i];
      if (target.cap > 0 && level[now] < level[target.to]) {
        int d = dfs(target.to, goal, min(val, target.cap));
        if (d > 0) {
          target.cap -= d;
          Graph[target.to][target.rev].cap += d;
          return d;
        }
      }
    }
    return 0;
  }
  int run(int s, int t) {
    int ans = 0;
    int f = 0;
    while (bfs(s), level[t] >= 0) {
      itr = vector<int>(Graph.size(), 0);
      while ((f = dfs(s, t, 1e9)) > 0) {
        ans += f;
      }
    }
    return ans;
  }
};

class HLDecomposition {
public:
  vector<vector<int>> vertexs;
  vector<int> depth;
  vector<int> backs;
  vector<int> connections;
  vector<int> zip, unzip;
  HLDecomposition(int n) {
    vertexs = vector<vector<int>>(n, vector<int>());
    depth = vector<int>(n);
    zip = vector<int>(n);
    unzip = zip;
  }
  void add_edge(int a, int b) {
    vertexs[a].push_back(b);
    vertexs[b].push_back(a);
  }
  int depth_dfs(int now, int back) {
    depth[now] = 0;
    for (auto x : vertexs[now]) {
      if (x == back)
        continue;
      depth[now] = max(depth[now], 1 + depth_dfs(x, now));
    }
    return depth[now];
  }
  void dfs(int now, int backing) {
    zip[now] = backs.size();
    unzip[backs.size()] = now;
    backs.push_back(backing);
    int now_max = -1;
    int itr = -1;
    for (auto x : vertexs[now]) {
      if (depth[x] > depth[now])
        continue;
      if (now_max < depth[x]) {
        now_max = depth[x];
        itr = x;
      }
    }
    if (itr == -1)
      return;
    connections.push_back(connections.back());
    dfs(itr, backing);
    for (auto x : vertexs[now]) {
      if (depth[x] > depth[now])
        continue;
      if (x == itr)
        continue;
      connections.push_back(zip[now]);
      dfs(x, backs.size());
    }
    return;
  }
  void build() {
    depth_dfs(0, -1);
    connections.push_back(-1);
    dfs(0, -1);
  }
  vector<pair<int, int>> query(int a, int b) {
    a = zip[a];
    b = zip[b];
    vector<pair<int, int>> ans;
    while (backs[a] != backs[b]) {
      if (a < b)
        swap(a, b);
      ans.push_back(mp(backs[a], a + 1));
      a = connections[a];
    }
    if (a > b)
      swap(a, b);
    ans.push_back(mp(a, b + 1));
    return ans;
  }
  int lca(int a, int b) {
    a = zip[a];
    b = zip[b];
    while (backs[a] != backs[b]) {
      if (a < b)
        swap(a, b);
      a = connections[a];
    }
    return unzip[min(a, b)];
  }
};
// by ei1333
// https://ei1333.github.io/luzhiled/snippets/structure/segment-tree.html
template <typename Monoid> struct SegmentTree {
  using F = function<Monoid(Monoid, Monoid)>;

  int sz;
  vector<Monoid> seg;

  const F f;
  const Monoid M1;

  SegmentTree(int n, const F f, const Monoid &M1) : f(f), M1(M1) {
    sz = 1;
    while (sz < n)
      sz <<= 1;
    seg.assign(2 * sz + 1, M1);
  }

  void set(int k, const Monoid &x) { seg[k + sz] = x; }

  void build() {
    for (int k = sz - 1; k > 0; k--) {
      seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]);
    }
  }

  void update(int k, const Monoid &x) {
    k += sz;
    seg[k] = x;
    while (k >>= 1) {
      seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]);
    }
  }

  Monoid query(int a, int b) {
    Monoid L = M1, R = M1;
    for (a += sz, b += sz; a < b; a >>= 1, b >>= 1) {
      if (a & 1)
        L = f(L, seg[a++]);
      if (b & 1)
        R = f(seg[--b], R);
    }
    return f(L, R);
  }

  Monoid operator[](const int &k) const { return seg[k + sz]; }

  template <typename C>
  int find_subtree(int a, const C &check, Monoid &M, bool type) {
    while (a < sz) {
      Monoid nxt = type ? f(seg[2 * a + type], M) : f(M, seg[2 * a + type]);
      if (check(nxt))
        a = 2 * a + type;
      else
        M = nxt, a = 2 * a + 1 - type;
    }
    return a - sz;
  }

  template <typename C> int find_first(int a, const C &check) {
    Monoid L = M1;
    if (a <= 0) {
      if (check(f(L, seg[1])))
        return find_subtree(1, check, L, false);
      return -1;
    }
    int b = sz;
    for (a += sz, b += sz; a < b; a >>= 1, b >>= 1) {
      if (a & 1) {
        Monoid nxt = f(L, seg[a]);
        if (check(nxt))
          return find_subtree(a, check, L, false);
        L = nxt;
        ++a;
      }
    }
    return -1;
  }

  template <typename C> int find_last(int b, const C &check) {
    Monoid R = M1;
    if (b >= sz) {
      if (check(f(seg[1], R)))
        return find_subtree(1, check, R, true);
      return -1;
    }
    int a = sz;
    for (b += sz; a < b; a >>= 1, b >>= 1) {
      if (b & 1) {
        Monoid nxt = f(seg[--b], R);
        if (check(nxt))
          return find_subtree(b, check, R, true);
        R = nxt;
      }
    }
    return -1;
  }
};

template <typename Monoid, typename OperatorMonoid = Monoid>
struct LazySegmentTree {
  using F = function<Monoid(Monoid, Monoid)>;
  using G = function<Monoid(Monoid, OperatorMonoid)>;
  using H = function<OperatorMonoid(OperatorMonoid, OperatorMonoid)>;

  int sz, height;
  vector<Monoid> data;
  vector<OperatorMonoid> lazy;
  const F f;
  const G g;
  const H h;
  const Monoid M1;
  const OperatorMonoid OM0;

  LazySegmentTree(int n, const F f, const G g, const H h, const Monoid &M1,
                  const OperatorMonoid OM0)
      : f(f), g(g), h(h), M1(M1), OM0(OM0) {
    sz = 1;
    height = 0;
    while (sz < n)
      sz <<= 1, height++;
    data.assign(2 * sz, M1);
    lazy.assign(2 * sz, OM0);
  }

  void set(int k, const Monoid &x) { data[k + sz] = x; }

  void build() {
    for (int k = sz - 1; k > 0; k--) {
      data[k] = f(data[2 * k + 0], data[2 * k + 1]);
    }
  }

  inline void propagate(int k) {
    if (lazy[k] != OM0) {
      lazy[2 * k + 0] = h(lazy[2 * k + 0], lazy[k]);
      lazy[2 * k + 1] = h(lazy[2 * k + 1], lazy[k]);
      data[k] = reflect(k);
      lazy[k] = OM0;
    }
  }

  inline Monoid reflect(int k) {
    return lazy[k] == OM0 ? data[k] : g(data[k], lazy[k]);
  }

  inline void recalc(int k) {
    while (k >>= 1)
      data[k] = f(reflect(2 * k + 0), reflect(2 * k + 1));
  }

  inline void thrust(int k) {
    for (int i = height; i > 0; i--)
      propagate(k >> i);
  }

  void update(int a, int b, const OperatorMonoid &x) {
    thrust(a += sz);
    thrust(b += sz - 1);
    for (int l = a, r = b + 1; l < r; l >>= 1, r >>= 1) {
      if (l & 1)
        lazy[l] = h(lazy[l], x), ++l;
      if (r & 1)
        --r, lazy[r] = h(lazy[r], x);
    }
    recalc(a);
    recalc(b);
  }

  Monoid query(int a, int b) {
    thrust(a += sz);
    thrust(b += sz - 1);
    Monoid L = M1, R = M1;
    for (int l = a, r = b + 1; l < r; l >>= 1, r >>= 1) {
      if (l & 1)
        L = f(L, reflect(l++));
      if (r & 1)
        R = f(reflect(--r), R);
    }
    return f(L, R);
  }

  Monoid operator[](const int &k) { return query(k, k + 1); }

  template <typename C>
  int find_subtree(int a, const C &check, Monoid &M, bool type) {
    while (a < sz) {
      propagate(a);
      Monoid nxt =
          type ? f(reflect(2 * a + type), M) : f(M, reflect(2 * a + type));
      if (check(nxt))
        a = 2 * a + type;
      else
        M = nxt, a = 2 * a + 1 - type;
    }
    return a - sz;
  }

  template <typename C> int find_first(int a, const C &check) {
    Monoid L = M1;
    if (a <= 0) {
      if (check(f(L, reflect(1))))
        return find_subtree(1, check, L, false);
      return -1;
    }
    thrust(a + sz);
    int b = sz;
    for (a += sz, b += sz; a < b; a >>= 1, b >>= 1) {
      if (a & 1) {
        Monoid nxt = f(L, reflect(a));
        if (check(nxt))
          return find_subtree(a, check, L, false);
        L = nxt;
        ++a;
      }
    }
    return -1;
  }

  template <typename C> int find_last(int b, const C &check) {
    Monoid R = M1;
    if (b >= sz) {
      if (check(f(reflect(1), R)))
        return find_subtree(1, check, R, true);
      return -1;
    }
    thrust(b + sz - 1);
    int a = sz;
    for (b += sz; a < b; a >>= 1, b >>= 1) {
      if (b & 1) {
        Monoid nxt = f(reflect(--b), R);
        if (check(nxt))
          return find_subtree(b, check, R, true);
        R = nxt;
      }
    }
    return -1;
  }
};

class KMP {
public:
  vector<ll> table;
  vector<ll> Pattern;
  KMP(vector<ll> a) { build(a); }
  void build(vector<ll> a) {
    Pattern = a;
    table = vector<ll>(a.size() + 1, -1);
    int j = -1;
    for (int i = 0; i < a.size(); ++i) {
      while (j >= 0 && Pattern[i] != Pattern[j]) {
        j = table[j];
      }
      table[i + 1] = ++j;
    }
    return;
  }
  vector<ll> search(vector<ll> a) {
    vector<ll> ans;
    for (int i = 0, k = 0; i < a.size(); ++i) {
      while (k >= 0 && a[i] != Pattern[k])
        k = table[k];
      ++k;
      if (k >= Pattern.size()) {
        ans.push_back(i - Pattern.size() + 1);
        k = table[k];
      }
    }
    return ans;
  }
};

unsigned long xor128() {
  static unsigned long x = 123456789, y = 362436069, z = 521288629,
                       w = 88675123;
  unsigned long t = (x ^ (x << 11));
  x = y;
  y = z;
  z = w;
  return (w = (w ^ (w >> 19)) ^ (t ^ (t >> 8)));
}

void init() {
  iostream::sync_with_stdio(false);
  cout << fixed << setprecision(20);
}

#define int ll

template <typename flow_t, typename cost_t> struct PrimalDual {
  const cost_t INF;

  struct edge {
    int to;
    flow_t cap;
    cost_t cost;
    int rev;
    bool isrev;
  };
  vector<vector<edge>> graph;
  vector<cost_t> potential, min_cost;
  vector<int> prevv, preve;

  PrimalDual(int V) : graph(V), INF(numeric_limits<cost_t>::max()) {}

  void add_edge(int from, int to, flow_t cap, cost_t cost) {
    graph[from].emplace_back(edge{to, cap, cost, (int)graph[to].size(), false});
    graph[to].emplace_back(
        edge{from, 0, -cost, (int)graph[from].size() - 1, true});
  }

  cost_t min_cost_flow(int s, int t, flow_t f) {
    int V = (int)graph.size();
    cost_t ret = 0;
    using Pi = pair<cost_t, int>;
    priority_queue<Pi, vector<Pi>, greater<Pi>> que;
    potential.assign(V, 0);
    preve.assign(V, -1);
    prevv.assign(V, -1);

    while (f > 0) {
      min_cost.assign(V, INF);
      que.emplace(0, s);
      min_cost[s] = 0;
      while (!que.empty()) {
        Pi p = que.top();
        que.pop();
        if (min_cost[p.second] < p.first)
          continue;
        for (int i = 0; i < graph[p.second].size(); i++) {
          edge &e = graph[p.second][i];
          cost_t nextCost = min_cost[p.second] + e.cost + potential[p.second] -
                            potential[e.to];
          if (e.cap > 0 && min_cost[e.to] > nextCost) {
            min_cost[e.to] = nextCost;
            prevv[e.to] = p.second, preve[e.to] = i;
            que.emplace(min_cost[e.to], e.to);
          }
        }
      }
      if (min_cost[t] == INF)
        return -1;
      for (int v = 0; v < V; v++)
        potential[v] += min_cost[v];
      flow_t addflow = f;
      for (int v = t; v != s; v = prevv[v]) {
        addflow = min(addflow, graph[prevv[v]][preve[v]].cap);
      }
      f -= addflow;
      ret += addflow * potential[t];
      for (int v = t; v != s; v = prevv[v]) {
        edge &e = graph[prevv[v]][preve[v]];
        e.cap -= addflow;
        graph[v][e.rev].cap += addflow;
      }
    }
    return ret;
  }

  void output() {
    for (int i = 0; i < graph.size(); i++) {
      for (auto &e : graph[i]) {
        if (e.isrev)
          continue;
        auto &rev_e = graph[e.to][e.rev];
        cout << i << "->" << e.to << " (flow: " << rev_e.cap << "/"
             << rev_e.cap + e.cap << ")" << endl;
      }
    }
  }
};

// base64 エンコード
bool encode_base64(const std::vector<unsigned char> &src, std::string &dst) {
  const std::string table(
      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/");
  std::string cdst;

  for (std::size_t i = 0; i < src.size(); ++i) {
    switch (i % 3) {
    case 0:
      cdst.push_back(table[(src[i] & 0xFC) >> 2]);
      if (i + 1 == src.size()) {
        cdst.push_back(table[(src[i] & 0x03) << 4]);
        cdst.push_back('=');
        cdst.push_back('=');
      }

      break;
    case 1:
      cdst.push_back(
          table[((src[i - 1] & 0x03) << 4) | ((src[i + 0] & 0xF0) >> 4)]);
      if (i + 1 == src.size()) {
        cdst.push_back(table[(src[i] & 0x0F) << 2]);
        cdst.push_back('=');
      }

      break;
    case 2:
      cdst.push_back(
          table[((src[i - 1] & 0x0F) << 2) | ((src[i + 0] & 0xC0) >> 6)]);
      cdst.push_back(table[src[i] & 0x3F]);

      break;
    }
  }

  dst.swap(cdst);

  return true;
}

int ut[30000];
int uf(int now) {
  if (now == ut[now])
    return now;
  return ut[now] = uf(ut[now]);
}
int um(int a, int b) {
  a = uf(a);
  b = uf(b);
  if (a == b)
    return 0;
  ut[a] = b;
  return 1;
}

int cnter[30000];

modint<MAX_MOD> dp[6000];
void solve() {
  int n;
  cin >> n;
  vector<int> inputs;
  REP(i, n) {
    int a;
    cin >> a;
    a--;
    a = max(a, -1LL);
    inputs.push_back(a);
    ut[i] = i;
  }
  int base_cnt = 0;
  REP(i, n) {
    if (inputs[i] == -1)
      continue;
    base_cnt += 1 - um(i, inputs[i]);
  }
  REP(i, n) { cnter[uf(i)]++; }
  vector<int> Finds;
  REP(i, n) {
    if (inputs[i] == -1) {
      Finds.push_back(cnter[uf(i)]);
    }
  }
  REP(i, Finds.size()) {
    for (int q = i; q >= 0; --q) {
      dp[q + 1] += dp[q] * Finds[i];
    }
    dp[0] += Finds[i];
  }
  modint<MAX_MOD> ans = (n - base_cnt);
  if (Finds.size() != 0)
    ans *= pows<modint<MAX_MOD>>(n - 1, Finds.size());
  modint<MAX_MOD> gekos = 1;
  dp[0] -= Finds.size();
  for (int i = 0; i < Finds.size(); ++i) {
    modint<MAX_MOD> hoge = dp[i] * gekos;
    if (Finds.size() - i - 1 != 0) {
      hoge *= pows<modint<MAX_MOD>>(n - 1, Finds.size() - i - 1);
    }
    ans -= hoge;
    gekos *= (i + 1);
  }
  cout << ans << endl;
}
#undef int
int main() {
  init();
  solve();
}