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#include <bits/stdc++.h>
#define pi pair<int, int>

using namespace std;

signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n, q;
  cin >> n >> q;
  vector<int> input(q);
  vector<int> curr_in(n + 1);
  int d = 0;
  int max_d = 0;
  int sum_d = 0;
  for (auto &x : input) {
    cin >> x;
    if (curr_in[x])
      d--;
    else
      d++;
    curr_in[x] ^= 1;
    max_d = max(d, max_d);
    sum_d += d;
  }

  /*
    O(30*sum_d*8) probabilistic. Chance of mistake 0.1%
    //30 tries, and each number has at most 8 prime divisors
  */
  auto probabilistic = [&]() {
    vector<int> sieve(n + 1, 1);
    vector<int> primes;
    vector<vector<int>> prime_divs(n + 1, vector<int>(1));
    prime_divs[0] = prime_divs[1] = vector<int>();
    for (int i = 2; i <= n; i++) {
      if (!sieve[i])
        continue;

      sieve[i] = true;
      prime_divs[i][0] = i;
      primes.push_back(i);
      for (long long j = (long long)i * i; j <= n; j += i) {
        sieve[j] = false;
        prime_divs[j][0] = i;
      }
    }

    for (int k = 2; k <= n; k++) {
      if (sieve[k])
        continue;
      int num = k;
      int q = prime_divs[k][0];
      while (num % q == 0)
        num /= q;
      for (auto prim : prime_divs[num]) {
        prime_divs[k].push_back(prim);
      }
    }

    d = 0;
    vector<pi> div_counts(n + 1);
    list<int> currently_in;
    vector<pair<int, list<int>::iterator>> is_in(n + 1);
    std::random_device rd;  // a seed source for the random number engine
    std::mt19937 gen(rd()); // mersenne_twister_engine seeded with rd()
    std::uniform_int_distribution<> distrib(0, INT_MAX);
    // idk the complexity of this constructor so just in case instead of doing
    // this for every d I'm just gonna take modulo each time cause i dont have
    // the time rn
    for (auto [generation, x] : views::enumerate(input)) {
      if (is_in[x].first == 0) {
        currently_in.push_back(x);
        is_in[x] = {x, prev(currently_in.end())};
        d++;
      } else {
        currently_in.erase(is_in[x].second);
        is_in[x].first = 0;
        d--;
      }

      vector<int> current{currently_in.begin(), currently_in.end()};
      int res = (d + 1) / 2;
      int minigen = 30 * generation;
      for (int _ = 0; _ < 30; _++) {
        int checked = distrib(gen) % d;
        for (int i = 0; i < d; i++) {
          int num = abs(current[i] - current[checked]);
          for (auto prim : prime_divs[num]) {
            if (div_counts[prim].second != minigen) {
              div_counts[prim] = {0, minigen};
            }
            div_counts[prim].first++;
            res = max(res, div_counts[prim].first + 1);
            //+1 bc of zero
          }
        }
        minigen++;
      }
      cout << res << '\n';
    }
  };

  auto basic = [&]() {
    for (int i = 0; i < curr_in.size(); i++)
      curr_in[i] = 0;
    vector<bool> sieve(n + 1, 1);
    vector<int> primes;
    for (int i = 2; i <= n; i++) {
      if (!sieve[i])
        continue;

      sieve[i] = true;
      primes.push_back(i);
      for (int j = i * i; j <= n; j += i)
        sieve[j] = false;
    }

    const int pn = primes.size();
    vector<vector<set<int>>> current_state(primes.size());
    for (int i = 0; i < pn; i++) {
      current_state[i].resize(primes[i]);
    }

    multiset<int> results;

    for (auto &x : input) {

      bool is_in = curr_in[x];
      curr_in[x] ^= 1;

      auto update = [&](int i) {
        auto to_change =
            results.find((int)current_state[i][x % primes[i]].size());
        if (is_in) {
          current_state[i][x % primes[i]].erase(x);
          results.insert(-1 + *to_change);
          results.erase(to_change);
        } else {
          current_state[i][x % primes[i]].insert(x);
          int num = 1;
          if (to_change != results.end()) {
            num = 1 + *to_change;
            results.erase(to_change);
          }

          results.insert(num);
        }
      };

      for (int i = 0; i < primes.size(); i++) {
        update(i);
      }

      cout << (results.empty() ? 0 : *prev(results.end())) << '\n';
    }
  };

  if(n <= 100 && q <= 1000){
    basic();
    return 0;
  }
  if (sum_d <= 1000000) {
    probabilistic();
    return 0;
  }

  if (n <= 8000 && n * q <= (long long)8000 * 1000) {
    basic();
    return 0;
  }

  if (sum_d <= 1900000) {
    probabilistic();
    return 0;
  }

  if (n <= 9000 && n * q <= (long long)9000 * 13000) {
    basic();
    return 0;
  }

  if(sum_d <= 2100000){
    probabilistic();
    return 0;
  }
  basic();
  return 0;
}