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#include <bits/stdc++.h>
using namespace std;

const int MAX_N = 10'000'000;
const int T = 20;
const int P = 2000;

struct vec : vector<int> {
    array<optional<size_t>, MAX_N + 1> where;

    bool add_or_remove(int a) {
        if (where[a]) {
            where[this->back()] = where[a];
            std::swap(this->at(where[a].value()), this->back());
            this->pop_back();
            where[a].reset();
        }
        else {
            where[a] = this->size();
            this->push_back(a);
        }
        return where[a].has_value();
    }

    pair<int, int> get_two(auto& rng) {
        auto i = rng() % this->size();
        auto j = rng() % (this->size() - 1);
        if (i == j) { ++j; }
        return {this->at(i), this->at(j)};
    }

    void clear() {
        this->clear();
        where = {};
    }
};

struct seg_tree {
    vector<int> data;
    int base;

    void set_size(int n) {
        base = bit_ceil((uint32_t)n);
        data.resize(2 * base);
    }

    void update(int i, int val, bool add) {
        i += base;
        if (add) {
            data[i] += val;
        }
        else {
            data[i] = val;
        }
        for (i /= 2; i; i /= 2) {
            data[i] = max(data[2 * i], data[2 * i + 1]);
        }
    }

    int get_max() {
        return data[1];
    }
};

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    vector<int> primes;
    vector<int> sieve(MAX_N + 1);
    for (int num = 2; num <= MAX_N; ++num) {
        if (sieve[num]) { continue; }
        primes.push_back(num);
        for (int i = num; i <= MAX_N; i += num) {
            sieve[i] = num;
        }
    }

    mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

    vector<seg_tree> cnt(P);
    for (int i = 0; i < P; ++i) {
        cnt[i].set_size(primes[i]);
    }
    seg_tree total;
    total.set_size(P);

    int n, q;
    cin >> n >> q;
    vec stones;
    vector<int> tmp(MAX_N + 1);
    while (q--) {
        int a;
        cin >> a;
        bool added = stones.add_or_remove(a);
        for (int i = 0; i < P; ++i) {
            cnt[i].update(a % primes[i], (added ? +1 : -1), true);
            total.update(i, cnt[i].get_max(), false);
        }

        if (stones.size() <= 2) {
            cout << stones.size() << '\n';
            continue;
        }

        auto check = [&](int mod) {
            int maxx = 0;
            for (auto& s : stones) {
                maxx = max(maxx, ++tmp[s % mod]);
            }
            for (auto& s : stones) {
                --tmp[s % mod];
            }
            return maxx;
        };

        int res = total.get_max();
        if (stones.size() < 1151) {
            for (int i = 0; i < T; ++i) {
                auto [x, y] = stones.get_two(rng);
                int dist = abs(x - y);
                int d = sieve[dist];
                if (d <= 17389) { continue; }
                res = max(res, check(d));
            }
        }
        cout << res << '\n';
    }
    return 0;
}