#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>

using namespace std;

typedef long long ll;

#define sz size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(c) (c).begin(), (c).end()
#define rep(i,a,b) for(ll i=(a);i<(b);++i)
#define clr(a, b) memset((a), (b) ,sizeof(a))
#define ctos(c) string(1,c)
#define print(x) cout<<#x<<" = "<<x<<endl;

#define MOD 1000000007

#define A 250

ll dh[60300];
ll dl[60300];
ll dd[60300];
ll dddh[300];
ll dddl[300];

ll geth(ll p){
	ll index = p/A;
	if(dddh[index]==-1){
		return dh[p];
	}
	else{
		return dddh[index];
	}
}

ll getl(ll p){
	ll index = p/A;
	if(dddl[index]==-1){
		return dl[p];
	}
	else{
		return dddl[index];
	}
}

int main(){
	ll n,q;
	cin>>n>>q;
	clr(dh,-1);
	clr(dl,-1);
	clr(dd,-1);
	clr(dddh,-1);
	clr(dddl,-1);
	set<ll> se;
	vector<pair<ll,ll> > vp;
	rep(i,0,q){
		ll a,b;
		cin>>a>>b;
		a++;b++;
		vp.pb(mp(a,b));
		se.insert(a);
		se.insert(b);
	}
	vector<ll> vse(all(se));
	map<ll,ll> ma;
	rep(i,0,vse.sz){
		dd[i+1]=vse[i];
		ma[vse[i]] = i+1;
	}
	vector<pair<ll,ll> > vp1;
	rep(i,0,vp.sz){
		vp1.pb(mp(ma[vp[i].fi],ma[vp[i].se]));
	}
	ll mx = 0;
	rep(i,0,vp1.sz){
		ll a1,b1;
		ll a = vp1[i].fi;
		ll b = vp1[i].se;
		ll pa = getl(a-1);
		if(pa==-1)a1 = a;
		else {
			if(dd[a]-1<=dd[geth(a-1)]){
				a1 = pa;
			}
			else{
				a1 = a;
			}
		}
		ll pb = geth(b+1);
		if(pb==-1)b1 = b;
		else {
			if(dd[getl(b+1)]<=dd[b]+1){
				b1 = pb;
			}
			else{
				b1 = b;
			}
		}
		ll index1 = a1/A;
		ll index2 = b1/A;
		rep(j,index1*A,(index1+1)*A){
			if(a1 <= j && j <= b1){
				dl[j] = a1;
				dh[j] = b1;
			}
		}
		rep(j,index2*A,(index2+1)*A){
			if(a1 <= j && j <= b1){
				dl[j] = a1;
				dh[j] = b1;
			}			
		}
		rep(j,index1+1,index2){
			dddl[j] = a1;
			dddh[j] = b1;
		}
		mx = max(mx,dd[b1]-dd[a1]+1);
		printf("%lld\n", mx);
	}
	return 0;
}