/* -*- coding: utf-8 -*-
 *
 * 674.cc: No.674 n連勤 - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

/* typedef */

typedef long long ll;
typedef pair<ll,ll> pll;
typedef set<pll> spll;

/* global variables */

spll rs;

/* subroutines */

inline void setmin(ll &a, ll b) { if (a > b) a = b; }
inline void setmax(ll &a, ll b) { if (a < b) a = b; }

/* main */

int main() {
  ll d;
  int q;
  scanf("%lld%d", &d, &q);

  ll maxl = 0;
  while (q--) {
    ll a, b;
    scanf("%lld%lld", &a, &b);
    b++;
    pll qr(a, b);

    spll::iterator sit = rs.lower_bound(qr);
    if (sit != rs.begin()) sit--;

    while (sit != rs.end() && sit->first <= qr.second) {
      ll ai = sit->first, bi = sit->second;
      spll::iterator eit = sit++;
      if (qr.first <= bi) {
	setmin(qr.first, ai);
	setmax(qr.second, bi);
	rs.erase(eit);
      }
    }

    rs.insert(qr);
    setmax(maxl, qr.second - qr.first);
    printf("%lld\n", maxl);
  }

  return 0;
}