#define _USE_MATH_DEFINES
#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define MT make_tuple
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
#define RT return
#define vv(a,b,c,d) vector<vector<a> >(b,vector<a>(c,d))
#define vvv(a,b,c,d,e) vector<vector<vector<a> > >(b,vv(a,c,d,e))
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;
using vll = vector<ll>;

using P = pair<ll, ll>;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(20);

    ll D;
    int Q;
    while (cin >> D >> Q) {
        vll A(Q), B(Q);
        ll re = 0;
        set<P> S;

        rep(q, Q) {
            cin >> A[q] >> B[q];

            ll lb = A[q], ub = B[q];
            for (auto it = S.lower_bound(mp(A[q] - 1, 0)); it != S.end(); ) {
                ll l, r;
                tie(r, l) = *it;
                if (l > B[q] + 1)break;
                smin(lb, l);
                smax(ub, r);
                it = S.erase(it);
            }
            
            S.insert(mp(ub, lb));
            smax(re, ub - lb + 1);
            cout << re << endl;
        }

    }
}