#define _USE_MATH_DEFINES
#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <complex>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
#include <iterator>
using namespace std;

int main()
{
    long long d;
    int q;
    cin >> d >> q;

    long long ans = 0;
    set<pair<long long, long long> > s;
    while(--q >= 0){
        long long a, b;
        cin >> a >> b;
        ++ b;

        auto it = s.lower_bound(make_pair(a, -1));
        while(it != s.end()){
            if(b < it->first)
                break;
            b = max(b, it->second);
            it = s.erase(it);
        }
        while(it != s.begin()){
            -- it;
            if(it->second < a)
                break;
            a = min(a, it->first);
            b = max(b, it->second);
            it = s.erase(it);
        }
        s.insert(make_pair(a, b));

        ans = max(ans, b - a);
        cout << ans << endl;
    }

    return 0;
}