#include <bits/stdc++.h>
#define int long long
using namespace std;
const int N = 3e5 + 5;
int n, d;
tuple<int, int, int> a[N];
struct lazyseg{
int seg[4 * N], lz[4 * N];
void push(int nd, int l, int r){
if(lz[nd] != 0){
seg[nd] += lz[nd];
if(l != r){
lz[nd * 2] += lz[nd];
lz[nd * 2 + 1] += lz[nd];
}
lz[nd] = 0;
}
}
void build(int nd, int l, int r){
if(l == r) return seg[nd] = get<0>(a[l]), void();
int md = (l + r) / 2;
build(nd * 2, l, md);
build(nd * 2 + 1, md + 1, r);
seg[nd] = max(seg[nd * 2], seg[nd * 2 + 1]);
}
void upd(int nd, int l, int r, int ql, int qr, int x){
push(nd, l, r);
if(r < ql || qr < l) return;
if(ql <= l && r <= qr){
lz[nd] += x;
push(nd, l, r);
return;
}
int md = (l + r) / 2;
upd(nd * 2, l, md, ql, qr, x);
upd(nd * 2 + 1, md + 1, r, ql, qr, x);
seg[nd] = max(seg[nd * 2], seg[nd * 2 + 1]);
}
}s;
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> d;
vector<pair<int, int>> cand = {{0, 0}};
for(int i = 1;i<=n;i++){
auto &[x, b, c] = a[i];
cin >> x >> b >> c;
cand.push_back({c, i});
}
sort(a + 1, a + n + 1);
a[n + 1] = {d, 0, 0};
sort(cand.begin(), cand.end());
cand.push_back({2e9, N - 1});
int ans = d;
s.build(1, 1, n + 1);
for(int i = 0;i<cand.size() - 1;i++){
s.upd(1, 1, n + 1, cand[i].second + 1, n + 1, -get<1>(a[cand[i].second]));
s.push(1, 1, n);
if(s.seg[1] > cand[i + 1].first) continue;
ans = min(ans, s.seg[1]);
}
cout << ans;
}
