#include<bits/stdc++.h>
#define rep(i,j,n) for(ll i=j;i<(ll)(n);i++)

using namespace std;
typedef long long ll;

struct interval_set{
    interval_set(){
        st.insert(make_pair(-(1LL << 60),-(1LL << 60)));
        st.insert(make_pair(1LL << 60,1LL << 60));
    }
    void insert(ll l,ll r){
        auto iter = st.lower_bound(make_pair(l,r));
        vector<pair<ll,ll>> erase_vec;

        ll left = l,right = r;
        for(auto iter_ = iter;;iter_++){
            if(max(iter_->first,left) > min(iter_->second,right)) break;
            erase_vec.push_back(*iter_);
            left = min(left,iter_->first);
            right = max(right,iter_->second);
        }
        iter--;
        for(auto iter_ = iter;;iter_--){
            if(max(iter_->first,left) > min(iter_->second,right)) break;
            erase_vec.push_back(*iter_);
            left = min(left,iter_->first);
            right = max(right,iter_->second);
        }

        for(auto _ : erase_vec)
            st.erase(_);
            
        st.insert(make_pair(left,right));
        max_len = max(max_len,right - left);
    }

    ll max_length(){
        return max_len;
    }


    set<pair<ll,ll>> st;
    ll max_len = 0;
};

int main(){
    cin.tie(nullptr);
    cout << fixed << setprecision(20);

    ll d,q; cin >> d >> q;
    vector<ll> a(q),b(q);
    rep(i,0,q) cin >> a[i] >> b[i];
    interval_set is;
    rep(i,0,q){
        is.insert(a[i],b[i]+1);
        cout << is.max_length() << endl;
    }
}