#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<iomanip>
#include<math.h>
#include<complex>
#include<queue>
#include<deque>
#include<stack>
#include<map>
#include<set>
#include<bitset>
#include<functional>
using namespace std;
#define REP(i,m,n) for(int i=(int)m ; i < (int) n ; ++i )
#define rep(i,n) REP(i,0,n)
typedef long long ll;
typedef pair<int,int> pint;
typedef pair<ll,int> pli;
const int inf=1e9+7;
const ll longinf=1LL<<60 ;
const ll mod=1e9+7 ;

int main(){
    ll d,q;
    cin>>d>>q;
    set<pair<ll,ll>> st;
    st.insert({longinf,longinf});
    st.insert({-longinf,-longinf});
    ll ret=0;
    while(q--){
        ll x,y;
        cin>>x>>y;
        ++y;
        auto itr=st.lower_bound({x,0});
        --itr;
        if(itr->second>=x){
            x=itr->first;
            y=max(itr->second,y);
            itr=st.erase(itr);
        }
        else itr++;
        ll res=y;
        while(itr->first<=y) {
            res=max(res,itr->second);
            itr=st.erase(itr);
        }
        st.insert({x,res});
        ret=max(res-x,ret);
        cout<<ret<<endl;  
    }
    return 0;
}