#include<iostream>
#include<set>
using namespace std;
long D;
int Q;
set<pair<long,long> >S;
main()
{
	cin>>D>>Q;
	long ans=0;
	for(int i=0;i<Q;i++)
	{
		long A,B;cin>>A>>B;
		B++;
		pair<long,long>now=make_pair(A,B);
		set<pair<long,long> >::iterator it=S.lower_bound(make_pair(A,-1));
		while(it!=S.end()&&it->first<=now.second)
		{
			if(now.second<it->second)now.second=it->second;
			it=S.erase(it);
		}
		while(it!=S.begin())
		{
			it--;
			if(now.first>it->second)break;
			if(now.first>it->first)now.first=it->first;
			it=S.erase(it);
		}
		if(ans<now.second-now.first)ans=now.second-now.first;
		S.insert(now);
		cout<<ans<<endl;
	}
}