#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int,int> pi;
#define f first
#define s second
#define FAST ios_base::sync_with_stdio(0); cin.tie(0);
const int maxn = 300010;
typedef pair<int,pi> pii;
#define p(x,y,z) pii(x,pi(y,z))
const int INF = LLONG_MAX/2;
int n,d;
vector <pii> v; //Bi, pos, Ai
vector <int> posv;
struct node {
int s,m,e,v, lazy;
node *l, *r;
node(int _s, int _e) {
s = _s; e = _e; m = (s+e)/2;
v = lazy = 0;
if (s != e) {
l = new node(s,m);
r = new node(m+1,e);
}
}
void push() {
if (lazy == 0) return;
v += lazy;
if (s != e) {
l -> lazy += lazy;
r -> lazy += lazy;
}
lazy = 0;
}
void up(int x, int y, int newv) {
if (s == x and e == y) lazy += newv;
else {
if (x > m) r -> up(x,y,newv);
else if (y <= m) l -> up(x,y,newv);
else l -> up(x,m,newv), r -> up(m+1,y,newv);
l -> push();
r -> push();
v = min(l -> v, r -> v);
}
}
int rmq() {
push();
return v;
}
}*root;
int32_t main() {
FAST
cin >> n >> d;
for (int i =0;i<n;i++) {
int pos,a,b; cin >> pos >> a >> b;
v.push_back(p(b,pos,a));
posv.push_back(pos);
}
v.push_back(p(d,d,0));
posv.push_back(d);
root = new node(0,n);
//cout << "HELLO\n";
sort(v.rbegin(),v.rend());
sort(posv.begin(),posv.end());
for (int i =0;i<=n;i++) {
//cout << i << "\n";
root -> up(i,i,-posv[i]);
}
int prevf = 0;
int ans = INF;
for (int i =0;i<(int)v.size();i++) {
int curf = v[i].f, x = v[i].s.f, ai = v[i].s.s;
//cout << "NEW: " << curf << " " << x << " " << ai << "\n";
root -> up(0ll,n, (curf - prevf));
int indx = lower_bound(posv.begin(),posv.end(),x) - posv.begin();
if (indx+1 <= n) root -> up(indx+1,n,ai);
int extra = root -> rmq();
if (extra >= 0) {
ans = min(ans, curf - extra);
}
prevf = curf;
}
cout << ans;
}
