#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<int, int>
pair<int, pii> A[300005];
pii B[300005];
int exis[300005];
struct node{
int s,e,m,val, lazy;
node *l, *r;
node(int _s, int _e){
s = _s, e = _e, m = (s + e)/2;
val = 0;
lazy = 0;
if(s != e){
l = new node(s, m);
r= new node(m+1, e);
}
}
void propo(){
if(lazy){
val += lazy;
if(s != e){
l->lazy += lazy;
r->lazy += lazy;
}
lazy = 0;
}
}
void update(int a, int b, int c){
if(a == s && b == e)lazy += c;
else{
if(b <= m)l->update(a,b,c);
else if(a > m)r->update(a,b,c);
else l->update(a,m,c), r->update(m+1,b,c);
l->propo(), r->propo();
val = min(l->val, r->val);
}
}
int query(int p){
propo();
if(s == e)return val;
if(p <= m)return l->query(p);
else return r->query(p);
}
}*root;
main(){
int n,d;cin >> n >> d;
root = new node(0, n+ 5);
for(int i=1;i<=n;i++){
cin >> A[i].first >> A[i].second.first >> A[i].second.second;
}
sort(A+1, A+n+1);
A[n+1] = {d,{0,0}};
for(int i=1;i<=n;i++)B[i] = {A[i].second.second, i};
sort(B+1, B+n+1);
int in = n ;
exis[0] = exis[n+1] = true;
multiset<int>s;
s.insert(0);
s.insert(n+1);
root->update(0,0,0);
root->update(n+1,n+1,-d);
int cnt = d;
while(in >= 1){
int x = B[in].first;
while(B[in].first == x){
int y = B[in].second;
multiset<int> :: iterator it = s.upper_bound(y);
it--;
int temp = root->query(*it);
root->update(y,y,temp + A[*it].first - A[y].first + A[*it].second.first);
root->update(y+1,n+1,A[y].second.first);
s.insert(y);
in--;
}
root->propo();
int mini = root->val;
mini = -mini;
if(mini <= x)cnt = min(cnt, mini);
}
cout << cnt;
}
