#include<bits/stdc++.h>
using namespace std;
#define int long long
#define inf 5e18
#define nl '\n'
const int N = 3e5+1;
int seg[4*N], lz[4*N], arr[N];
void lazy(int l, int r, int p){
if(lz[p] != 0){
seg[p] += lz[p];
if(l != r){
lz[p*2] += lz[p];
lz[p*2+1] += lz[p];
}
lz[p] = 0;
}
}
void build(int l, int r, int p){
if(l == r){
seg[p] = arr[l];
return;
}
int m = (l+r)/2;
build(l, m, p*2);
build(m+1, r, p*2+1);
seg[p] = min(seg[p*2], seg[p*2+1]);
}
void upd(int l, int r, int p, int ql, int qr, int v){
lazy(l, r, p);
if(qr < l or r < ql) return;
if(ql <= l and r <= qr){
lz[p] += v;
lazy(l, r, p);
return;
}
int m = (l+r)/2;
upd(l, m, p*2, ql, qr, v);
upd(m+1, r, p*2+1, ql, qr, v);
seg[p] = min(seg[p*2], seg[p*2+1]);
}
int qry(){
return -seg[1];
}
void upd(int ql, int qr, int v){
upd(0, N-1, 1, ql, qr, v);
}
inline void solve(){
int n, d;
cin>>n>>d;
tuple<int,int,int> st[n];
for(int i=0; i<n; i++){
int x, a, b;
cin>>x>>a>>b;
st[i] = {x, a, b};
}
sort(st, st+n);
for(int i=0; i<n; i++){
auto [x, a, b] = st[i];
arr[i] = -x;
}
arr[n] = -d;
for(int i=0; i<n; i++){
auto [x, a, b] = st[i];
st[i] = {b, a, i};
}
sort(st, st+n, greater<>());
build(0, N-1, 1);
int mn = qry();
for(int i=0; i<n; i++){
auto [b, a, ix] = st[i];
upd(ix+1, n, a);
if(b >= qry()) mn = min(mn, qry());
}
cout<<mn;
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(NULL);cout.tie(NULL);
int t = 1;
//cin>>t;
while(t--) solve();
return 0;
}
