#include<bits/stdc++.h>
using namespace std;
using ll = long long;
template<class T> using vt = vector<T>;
template<class T> using vvt = vector<vt<T>>;
template<class T> using ttt = tuple<T,T>;
using tii = tuple<int,int>;
using vi = vector<int>;
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define pb push_back
#define mt make_tuple
#define ALL(a) (a).begin(),(a).end()
#define FST first
#define SEC second
#define DEB cerr<<"!"<<endl
#define SHOW(a,b) cerr<<(a)<<" "<<(b)<<endl
#define DIV int(1e9+7)
const int INF = (INT_MAX/2);
const ll LLINF = (LLONG_MAX/2);
const double eps = 1e-8;
//const double PI = M_PI;  
inline ll pow(ll x,ll n,ll m){ll r=1;while(n>0){if((n&1)==1)r=r*x%m;x=x*x%m;n>>=1;}return r%m;}
inline ll lcm(ll d1, ll d2){return d1 / __gcd(d1, d2) * d2;}

/*Coding Space*/

//区間管理する奴 O(log 値域)
template<class T>
struct RangeMarge{
  map<T, T> m; // m[r] = l にすると実装楽
  pair<T,T> insert(T l, T r){ // [l,r]が返り値（実際の区間）
    auto l_it = m.lower_bound(l);
    auto r_it = m.lower_bound(r);
    if(l_it != m.end() && l_it->second <= l) l = l_it->second;
    if(r_it != m.end() && r_it->second <= r) r = r_it->first;
    m.erase(l_it, m.upper_bound(r));
    m[r] = l;
    return make_pair(l,r);
  }
  pair<T,T> get(T p){ //pが含まれる領域を返す
    auto p_it = m.upper_bound(p);
    return (p_it == m.end()?make_pair(T(),T()):*p_it);
  }
};

int main(){
  ll d,q; cin >> d >> q;
  ll ans = 0;
  RangeMarge<ll> rm;
  rep(i,q){
    ll a,b; cin >> a >> b;
    auto p = rm.insert(a,++b);
    ans = max(ans, p.second - p.first);
    cout << ans << endl;
  }
}