#include <bits/stdc++.h>
#define REP(i, s, n) for (int i = s; i < (int)(n); i++)
#define ALL(a) a.begin(), a.end()
#define MOD 1000000007
using namespace std;
using ll = long long;

int main() {
    ll D; int Q; cin >> D >> Q;

    set<pair<ll, ll>> S;
    S.insert({-1, -1});
    S.insert({D, D});

    ll consecutive = 0;
    while (Q--) {
        ll a, b; cin >> a >> b; b++; // [a, b)

        auto itr = prev(S.lower_bound({a, 0}));
        if (itr->first <= a && a <= itr->second) a = itr->first;

        for (auto itr = S.lower_bound({a, 0}); a <= itr->first && itr->first <= b; ) {
            b = max(b, itr->second);
            itr = S.erase(itr);
        }

        S.insert({a, b});
        consecutive = max(consecutive, b - a);
        cout << consecutive << endl;
    }    
    return 0;
}