#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
vector<pair<ll, ll> > vec;
struct node {
ll s, e, m;
ll mn, lz;
node *l, *r;
node(ll _s, ll _e): s(_s), e(_e), m((_s+_e)/2), lz(0) {
if (s == e) {
mn = -vec[s].first;
return;
}
l = new node(s, m);
r = new node(m+1, e);
mn = min(l->mn, r->mn);
}
void prop() {
l->update(s, m, lz);
r->update(m+1, e, lz);
lz = 0;
mn = min(l->mn, r->mn);
}
void update(ll x, ll y, ll v) {
if (x > y) return;
if (x <= s && y >= e) {
mn += v;
lz += v;
return;
}
if (lz != 0) prop();
if (x <= m) l->update(x, y, v);
if (y >= m+1) r->update(x, y, v);
mn = min(l->mn, r->mn);
}
};
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
ll n, d, x, a, b, ans;
vector<tuple<ll, ll, ll> > vec2;
cin >> n >> d;
ans = d;
for (ll i=0; i<n; i++) {
cin >> x >> a >> b;
vec.emplace_back(x, i);
vec2.emplace_back(b, a, x);
}
vec.emplace_back(d, n);
vec2.emplace_back(2000000000, 0, d);
sort(vec.begin(), vec.end());
ll cnt = n+1;
for (ll i=n; i>=0; i--) {
if (i != n && vec[i].first != vec[i+1].first) cnt = i + 1;
get<2>(vec2[vec[i].second]) = cnt;
}
sort(vec2.begin(), vec2.end());
node *root = new node(0, n);
for (ll i=0; i<n; i++) {
root->update(get<2>(vec2[i]), n, get<1>(vec2[i]));
}
ll left = 0;
for (ll i=0; i<=n; i++) {
root->update(0, n, get<0>(vec2[i]) - (i == 0 ? 0 : get<0>(vec2[i-1])));
if (i < n-1 && get<0>(vec2[i]) == get<0>(vec2[i+1])) continue;
while (get<0>(vec2[left]) != get<0>(vec2[i])) {
root->update(get<2>(vec2[left]), n, -get<1>(vec2[left]));
left++;
}
if (root->mn < 0) continue;
ans = min(ans, get<0>(vec2[i]) - root->mn);
}
cout << ans;
}
