#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<complex>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<utility>
#include<tuple>
using namespace std;
typedef long long ll;
typedef unsigned int ui;
const ll mod = 1000000007;
const ll INF = (ll)1000000007 * 1000000007;
typedef pair<int, int> P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define Per(i,sta,n) for(int i=n-1;i>=sta;i--)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
typedef long double ld;
typedef complex<ld> Point;
const ld eps = 1e-8;
const ld pi = acos(-1.0);
typedef pair<ll, ll> LP;

int q;
ll d;
set<LP> se; 

void solve(){
  cin >> d >> q;
  ll ans=0;
  rep(i,q){
    auto id=se.begin();
    //rep(i,se.size()){
      //cout << (*id).first << " " << (*id).second << " " << endl;
      //id++;
    //}
    ll a,b;
    cin >> a >> b;b++;
    auto idx=se.upper_bound(LP(a,INF));
    if(se.empty()){
      ans=max(ans,b-a);
      se.insert(LP(a,b));
      cout << ans << endl;
      continue;
    }
    if(idx==se.begin()){
      while((*idx).first<=b){
        b=max(b,(*idx).second);
        idx=se.erase(idx);
        if(idx==se.end()) break;
      }
      ans=max(ans,b-a);
      se.insert(LP(a,b));
    }
    else{
      idx--;
      if((*idx).second<a){
        idx++;
      }
      else{
        a=min(a,(*idx).first);
        b=max(b,(*idx).second);
      }
      if(idx==se.end()){
        ans=max(ans,b-a);
        se.insert(LP(a,b));
        cout << ans << endl;
        continue;
      }
      while((*idx).first<=b){
        b=max(b,(*idx).second);
        idx=se.erase(idx);
        if(idx==se.end()) break;
      }
      ans=max(ans,b-a);
      se.insert(LP(a,b));
    }
    cout << ans << endl;
  }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(50);
    solve();
}