#ifdef ONLINE_JUDGE
#pragma GCC target("avx")
#endif

#ifndef LOCAL
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#else
#define _GLIBCXX_DEBUG
#endif

#include <iostream>
#include <string>
#include <vector>
#include <iomanip>
#include <algorithm>
#include <queue>
#include <map>
#include <stack>
#include <cmath>
#include <functional>
#include <set>
#include <numeric>
#include <bitset>
#include <cassert>

using std::cerr;
using std::cin;
using std::cout;
using std::pair;
using std::string;
using std::vector;

//region
#define rep(i, n) for (std::uint32_t i = 0; i < (n); ++i)
using ll = long long;
using ld = long double;
using uint = unsigned int;
using ull = unsigned long long;
using usize = std::size_t;
using vint = vector<int>;
using vlong = vector<ll>;
using pii = pair<int, int>;
template <typename T> using VV = vector<vector<T>>;
template <typename T> using priority_queue_g = std::priority_queue<T, vector<T>, std::greater<>>;

//vector<string> split(const string &s, const string &delim) {
//  vector<string> res;
//  string::size_type pos = 0;
//  while (true) {
//    const size_t found = s.find(delim, pos);
//    if (found == std::string::npos) { res.push_back(s.substr(pos)); break; }
//    res.push_back(s.substr(pos, found - pos));
//    pos = found + delim.size();
//  }
//  return res;
//}

template<typename T>
string join(vector<T> &vec, const string &sep) {
  size_t size = vec.size();
  if (!size) return "";
  std::stringstream ss;
  for (size_t i : range(vec.size() - 1)) ss << vec[i] << sep;
  ss << vec.back();
  return ss.str();
}

template<typename T, typename U>
std::istream &operator>>(std::istream &is, pair<T, U> &pair) { return is >> pair.first >> pair.second; }

template<typename T>
std::istream &operator>>(std::istream &is, vector<T> &vec) { for (T &x : vec) is >> x; return is; }

template<typename Iter>
inline void print(const Iter &first, const Iter &last, const std::string &d = " ", bool endline = true) {
  cout << *first;
  for (Iter iter = first + 1; iter < last; ++iter) cout << d << *iter;
  if (endline) cout << "\n";
}

constexpr ll powmod(ll a, ull b, uint p) {
  ll res = 1;
  while (b > 0) {
    if (b % 2) res = res * a % p;
    a = a * a % p;
    b >>= 1u;
  }
  return res;
}

constexpr ll pow(ll a, ll b) {
  ll res = 1;
  while (b > 0) {
    if (b % 2) res = res * a;
    a = a * a;
    b >>= 1u;
  }
  return res;
}

template<typename T, std::enable_if_t<std::is_integral_v<T>, nullptr_t>* = nullptr>
struct RangeIterator {
    RangeIterator(T current, T step) : _current(current), _step(step) {}

    constexpr bool operator!=(RangeIterator& other) const noexcept {
      return _step < 0 ? _current > other._current : _current < other._current;
    }

    RangeIterator<T> operator++() noexcept { _current += _step; return *this; }

    constexpr T operator*() const noexcept { return _current; }

private:
    T _current, _step;
};

template<typename T, std::enable_if_t<std::is_integral_v<T>, nullptr_t>* = nullptr>
struct range {
    range(T stop) : range(0, stop) {}
    range(T start, T stop, T step = 1) : _start(start), _stop(stop), _step(step) {}

    RangeIterator<T> begin() const noexcept { return RangeIterator(_start, _step); }
    RangeIterator<T> end() const noexcept { return RangeIterator(_stop, _step); }
private:
    T _start, _stop, _step;
};

template<typename T>
range<T> rev_range(T stop) { return range(stop - 1, -1, -1); }

template<class T, class U, typename std::enable_if_t<std::is_convertible<U, T>::value, nullptr_t>* = nullptr>
bool chmax(T &a, const U &b) { return a < T(b) && (a = T(b), true); }

template<class T, class U, typename std::enable_if_t<std::is_convertible<U, T>::value, nullptr_t>* = nullptr>
bool chmin(T &a, const U &b) { return a > T(b) && (a = T(b), true); }

template<typename T>
void bsort(vector<T> &v) { std::sort(v.begin(), v.end()); }

template<typename T>
void rsort(vector<T> &v) { std::sort(v.begin(), v.end(), std::greater<T>()); }

struct io_init {
    io_init() {
      cin.tie(nullptr); cout.tie(nullptr);
      std::ios::sync_with_stdio(false);
      cout << std::fixed << std::setprecision(16);
    }
} io_init_nouse;
//endregion

template <typename T>
vector<T> input_vec(usize n, std::make_signed_t<T> offset = 0) {
  vector<T> res(n); cin >> res;
  for (usize i : range(n)) res[i] += offset;
  return res;
}

template <typename T> std::vector<T> make_vec(std::size_t n) { return std::vector<T>(n); }

template <typename T, typename ...Tail>
auto make_vec(std::size_t n, Tail... tail) { return std::vector(n, make_vec<T>(tail...)); }

void solve();

int main() {
  solve();
}

#include "testlib.h"

void solve() {
  registerValidation();

  usize n = inf.readInt(1, 200000);
  inf.readEoln();
  vector<int> a = inf.readIntegers(n, 0, 1);
  inf.readEoln();
  inf.readEof();
}