#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(x, a, b) for(auto x=a;(a<b?x<b:x>b);(a<b?x++:x--))
#define all(a) a.begin(), a.end()
#define srtvc(a) sort(all(a))
#define bcsrtvc(a) sort(all(a), greater<__typeof__(a[0])>())
#define ppf pop_front
#define ppb pop_back
#define pf push_front
#define pb push_back
#define ef emplace_front
#define eb emplace_back
#define fr first
#define sc second
#define pq priority_queue
#define pii pair<int, int>
#define vc vector
#define dq deque
#define sz(a) a.size()
#define mnto(x,y) x = min(x, (__typeof__(x))y)
#define mxto(x,y) x = max(x, (__typeof__(x))y)
#define setval(arr, x) memset(arr, x, sizeof(arr))
template<typename T>
using vv = vc<vc<T>>;
const int MAXN = 3e5+5;
int arr[MAXN];
struct SegTree {
struct Node {
int l, r, mid;
int val = 0, lz = 0;
Node *L = nullptr, *R = nullptr;
Node(int _l, int _r) : l(_l), r(_r) {
mid = (l + r) >> 1;
if (l != r) {
L = new Node(l, mid);
R = new Node(mid+1, r);
}
}
void apply(int v) {
val += v;
lz += v;
}
void push() {
if (lz == 0 || l == r) return;
L->apply(lz);
R->apply(lz);
lz = 0;
}
void pull() {
val = min(L->val, R->val);
}
void build() {
if (l == r) {
val = arr[l];
return;
}
L->build();
R->build();
pull();
}
void update(int ql, int qr, int v) {
if (qr < l || r < ql) return;
if (ql <= l && r <= qr) {
apply(v);
return;
}
push();
L->update(ql, qr, v);
R->update(ql, qr, v);
pull();
}
int qryMin() { return val; }
};
Node* root;
int n;
SegTree(int _n) : n(_n) {
root = new Node(0, n-1);
}
void build() { root->build(); }
void update(int l, int r, int v) { root->update(l, r, v); }
int qry() { return -root->qryMin(); }
};
int32_t main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int n, d;
cin >> n >> d;
tuple<int, int, int> st[n];
rep(i, 0, n) {
int x, a, b;
cin >> x >> a >> b;
st[i] = {x, a, b};
}
sort(st, st+n);
rep(i, 0, n) {
auto [x, a, b] = st[i];
arr[i] = -x;
st[i] = {b, a, i};
}
arr[n] = -d;
sort(st, st+n, greater<>());
SegTree seg(MAXN);
seg.build();
int mn = seg.qry();
rep(i, 0, n) {
auto [b, a, ix] = st[i];
seg.update(ix+1, n, a);
if (b >= seg.qry()) mnto(mn, seg.qry());
}
cout << mn;
}
