#include #define ll long long #define INF 1000000005 #define MOD 1000000007 #define EPS 1e-10 #define rep(i,n) for(int i=0;i<(int)(n);++i) #define rrep(i,n) for(int i=(int)(n)-1;i>=0;--i) #define srep(i,s,t) for(int i=(int)(s);i<(int)(t);++i) #define each(a,b) for(auto& (a): (b)) #define all(v) (v).begin(),(v).end() #define len(v) (int)(v).size() #define zip(v) sort(all(v)),v.erase(unique(all(v)),v.end()) #define cmx(x,y) x=max(x,y) #define cmn(x,y) x=min(x,y) #define fi first #define se second #define pb push_back #define show(x) cout<<#x<<" = "<<(x)< P; typedef pair pll; typedef vector vi; typedef vector vvi; typedef vector vl; typedef vector vvl; typedef vector vd; typedef vector

vp; typedef vector vs; const int MAX_N = 100005; //セグ木で持てないくらい大きい範囲の(0,1)の区間更新のクエリに答える //この実装では最終的に和を答える template class UpdateSet { private: using ptt = pair; T inf; multiset mx; public: set st; UpdateSet() : inf(numeric_limits::max()){ mx = {0}; }; //[l,r)をk(0,1)に更新 void update(T l,T r,int k){ T lb = l, rb = r; while(1){ auto it = st.lower_bound(ptt(l,-inf)); if(it == st.end()){ break; } ptt p = *it; if(p.fi >= r){ break; } st.erase(it); mx.erase(mx.find(p.se-p.fi)); if(p.se > r){ rb = max(rb,p.se); break; } } auto it = st.lower_bound(ptt(l,-inf)); if(it != st.begin()){ --it; ptt p = *it; if(p.se >= l){ st.erase(it); mx.erase(mx.find(p.se-p.fi)); lb = min(lb,p.fi); } if(p.se > r){ rb = max(rb,p.se); } } if(k == 1){ st.insert(ptt(lb,rb)); mx.insert(rb-lb); } } T query(){ return *(--mx.end()); } }; int main() { cin.tie(0); ios::sync_with_stdio(false); ll d; int q; cin >> d >> q; UpdateSet us; rep(i,q){ ll a,b; cin >> a >> b; us.update(a,b+1,1); cout << us.query() << "\n"; } return 0; }