#include <bits/stdc++.h>
using namespace std;
using ll = long long;
struct segment_tree {
int n;
vector<ll> tree, lazy;
segment_tree(int _n) : n(_n), tree(4*n, -1e18), lazy(4*n) {}
void push(int u, int tl, int tr) {
tree[u] += lazy[u];
if(tl != tr) {
lazy[2*u] += lazy[u];
lazy[2*u+1] += lazy[u];
}
lazy[u] = 0;
}
void update(int u, int tl, int tr, int l, int r, ll v) {
push(u, tl, tr);
if(tl > r || l > tr) return ;
if(l <= tl && tr <= r) {
lazy[u] += v;
push(u, tl, tr);
return ;
}
int tm = (tl + tr) / 2;
update(2*u, tl, tm, l, r, v);
update(2*u+1, tm+1, tr, l, r, v);
tree[u] = max( tree[2*u], tree[2*u+1] );
}
ll query(int u, int tl, int tr, int l, int r) {
if(tl > r || l > tr) return -1e18;
push(u, tl, tr);
if(l <= tl && tr <= r) return tree[u];
int tm = (tl + tr) / 2;
return max( query(2*u, tl, tm, l, r), query(2*u+1, tm+1, tr, l, r) );
}
void update(int l, int r, ll v) { update(1, 1, n, l, r, v); }
ll query(int l, int r) { return query(1, 1, n, l, r); }
};
signed main() {
int n, m; cin >> n >> m;
vector<array<int, 3> > a(n+1);
map<int, vector<int> > mp;
for(int i=1; i<=n; i++) {
cin >> a[i][0] >> a[i][1] >> a[i][2];
}
a.push_back({ m, 0, m });
sort(a.begin()+1, a.end());
for(int i=1; i<=n+1; i++)
mp[-a[i][2]].push_back(i);
ll ans = 1e9; n++;
segment_tree sgt(n);
for(auto [x, vec] : mp) {
ll d = -x;
for(int i : vec) {
sgt.update(i, i, (ll)1e18 + a[i][0]);
sgt.update(i+1, n, -a[i][1]);
}
ll mx = sgt.query(1, 1, n, 1, n);
if(d >= mx) ans = min(ans, mx);
}
cout << ans << '\n';
}
