#include <bits/stdc++.h> using namespace std; #define ll long long const ll nx=3e5+5; ll n, d, x[nx], a[nx], b[nx], t, cx[nx], rv[nx], res; map<ll, vector<ll>> mp; map<ll, ll> cmp; struct segtree { ll mn[4*nx], lz[4*nx]; void build(int l, int r, int i) { if (l==r) return mn[i]=-rv[l], void(); int md=(l+r)/2; build(l, md, 2*i); build(md+1, r, 2*i+1); mn[i]=min(mn[2*i], mn[2*i+1]); } void pushlz(int l, int r, int i) { mn[i]+=lz[i]; if (l!=r) lz[2*i]+=lz[i], lz[2*i+1]+=lz[i]; lz[i]=0; } void update(int l, int r, int i, int ql, int qr, int vl) { pushlz(l, r, i); if (qr<l||r<ql||qr<ql) return; if (ql<=l&&r<=qr) return lz[i]=vl, pushlz(l, r, i); int md=(l+r)/2; update(l, md, 2*i, ql, qr, vl); update(md+1, r, 2*i+1, ql, qr, vl); mn[i]=min(mn[2*i], mn[2*i+1]); } } s; int main() { cin.tie(NULL)->sync_with_stdio(false); cin>>n>>d; for (int i=1; i<=n; i++) cin>>x[i]>>a[i]>>b[i], mp[b[i]].push_back(i), cmp[x[i]]=0; cmp[d]=0; for (auto &[x, y]:cmp) y=++t, rv[t]=x; for (int i=1; i<=n; i++) cx[i]=cmp[x[i]]; s.build(1, t, 1); res=d; for (auto itr=mp.rbegin(); itr!=mp.rend(); itr++) { vector<ll> event=itr->second; ll bound=itr->first; for (auto idx:event) s.update(1, t, 1, cx[idx]+1, t, a[idx]); if (-s.mn[1]<=bound) res=min(res, -s.mn[1]); } cout<<res; }