#include <bits/stdc++.h>
using namespace std;
#define _MACRO(_1, _2, _3, NAME, ...) NAME
#define _repl(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define _rep(i,n) _repl(i,0,n)
#define rep(...) _MACRO(__VA_ARGS__, _repl, _rep)(__VA_ARGS__)
#define pb push_back
#define all(x) begin(x),end(x)
#define uniq(x) sort(all(x)),(x).erase(unique(all(x)),end(x))
#ifdef LOCAL
#define dbg(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
void _dbg(string){cerr<<endl;}
template<class H,class... T> void _dbg(string s,H h,T... t){int l=s.find(',');cerr<<s.substr(0,l)<<" = "<<h<<", ";_dbg(s.substr(l+1),t...);}
template<class T,class U> ostream& operator<<(ostream &o, const pair<T,U> &p){o<<"("<<p.first<<","<<p.second<<")";return o;}
template<class T> ostream& operator<<(ostream &o, const vector<T> &v){o<<"[";for(T t:v){o<<t<<",";}o<<"]";return o;}
#else
#define dbg(...) {}
#endif

template<class T>
class RangeMap : public map<T, T> {
// this internally stores range [l,r).
public:
  auto get(T v) const {
    auto it = this->upper_bound(v);
    if(this->empty() || it == this->begin() || (--it)->second <= v) return this->end();
    return it;
  }
  auto add(T l, T r) { // [l,r), returns new range
    assert(l<r);
    auto itl = this->upper_bound(l), itr = this->upper_bound(r);
    if(itl != this->begin() && prev(itl)->second >= l) {
      itl--;
    }
    if(itl != itr) {
      l = min(l, itl->first);
      r = max(r, prev(itr)->second);
      this->erase(itl, itr);
    }
    return this->emplace(l, r).first;
  }
  // void remove(T l, T r) { /* TODO */ }
};

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

  long ans = 0;

  RangeMap<long> m;
  rep(i,q){
    long l,r;
    cin>>l>>r;
    r++;
    auto itr = m.add(l,r);
    ans = max(ans, itr->second - itr->first);
    cout << ans << endl;
  }

  return 0;
}