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

class RangeSet{
private:
    const long long INF = 1e18 + 1e8;
    long long max_range;
    set<pair<long long, long long>> data;  // stores the ranges [L, R)
public:
    RangeSet(): max_range(0), data(){
        data.emplace(-INF, -INF);
        data.emplace(INF, INF);
    }
    void insert(long long L, long long R){        // Insert a range [L, R) to the set.
//        if (L >= R) return;
        auto it = data.lower_bound(make_pair(L, R));
        if (L == it->first) return;   // [L, R) is covered by *it. L1 == L < R <= R1
        if (L <= (--it)->second){
            L = it->first;
        }else{
            ++it;
        }
        while (it->first <= R){
            if (R < it->second) R = it->second;
            it = data.erase(it);
        }
        data.insert(it, make_pair(L, R));
        if (max_range < R - L) max_range = R - L;
    }
    long long get_max_range(){
        return this->max_range;
    }
};


int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    long long D;
    int Q;
    cin >> D >> Q;
    vector<pair<long long, long long>> ABs(Q);
    for (auto & ab: ABs) cin >> ab.first >> ab.second;
    RangeSet rset;
    for (auto & ab: ABs){
        rset.insert(ab.first, ab.second + 1LL);
        cout << rset.get_max_range() << '\n';
    }
    return 0;
}