#include <bits/stdc++.h>
using namespace std;
#define int long long
#define all(x) (x).begin(), (x).end()
#define sz(x) (int) (x).size()
const int MXN = 3e5 + 5, INF = 1e18;
int N, D;
int tree[4 * MXN], lazy[4 * MXN], tree_build[MXN];
array<int, 3> A[MXN];
int merge(int x, int y) {
return min(x, y);
}
void build(int i, int l, int r) {
if (l == r) {
tree[i] = tree_build[l];
return;
}
int mid = (l + r) / 2;
build(2 * i, l, mid);
build(2 * i + 1, mid + 1, r);
tree[i] = merge(tree[2 * i], tree[2 * i + 1]);
}
void propagate(int i, int l, int r) {
if (lazy[i] == 0) return;
tree[i] += lazy[i];
if (l != r) {
lazy[2 * i] += lazy[i];
lazy[2 * i + 1] += lazy[i];
}
lazy[i] = 0;
}
void increment(int i, int l, int r, int ql, int qr, int val) {
propagate(i, l, r);
if (l > qr || r < ql) return;
if (l >= ql && r <= qr) {
lazy[i] += val;
propagate(i, l, r);
return;
}
int mid = (l + r) / 2;
increment(2 * i, l, mid, ql, qr, val);
increment(2 * i + 1, mid + 1, r, ql, qr, val);
tree[i] = merge(tree[2 * i], tree[2 * i + 1]);
}
int query(int i, int l, int r, int ql, int qr) {
propagate(i, l, r);
if (l > qr || r < ql) return INF;
if (l >= ql && r <= qr) return tree[i];
int mid = (l + r) / 2;
return merge(query(2 * i, l, mid, ql, qr), query(2 * i + 1, mid + 1, r, ql, qr));
}
void increment(int l, int r, int val) { increment(1, 0, N - 1, l, r, val); }
int query(int l, int r) { return query(1, 0, N - 1, l, r); }
void deactivate(int idx, int nxt) {
if (nxt > N - 1) return;
increment(nxt, N - 1, -A[idx][1]);
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cin >> N >> D;
for (int i = 0; i < N; i++)
cin >> A[i][0] >> A[i][1] >> A[i][2];
sort(A, A + N);
A[N] = {D, 0, D};
N++;
vector<pair<int, int>> sorted_b;
int fuel_sum = 0;
int ptr = 0;
for (int i = 0; i < N; i++) {
while (ptr < N && A[ptr][0] != A[i][0])
fuel_sum += A[ptr++][1];
tree_build[i] = -A[i][0] + fuel_sum;
sorted_b.emplace_back(A[i][2], i);
}
build(1, 0, N - 1);
sort(all(sorted_b));
vector<int> nxt(N, N + 2);
for (int i = 0, j = 0; i < N; i++) {
for (; j < N && A[i][0] == A[j][0]; j++);
// cout << j << "\n";
nxt[i] = j;
// cout << i << " " << nxt[i] << "\n";
while (i < j)
nxt[i++] = j;
i--;
// cout << i << " " << nxt[i] << "\n";
}
// cout << N << "\n";
// for (int k = 0; k < N; k++)
// cout << nxt[sorted_b[k].second] << " ";
// cout << "\n\n";
for (int i = 0, j = 0, last = 0; i < sz(sorted_b); i++) {
increment(0, N - 1, sorted_b[i].first - last);
last = sorted_b[i].first;
while (j <= i && sorted_b[j].first < sorted_b[i].first) {
deactivate(sorted_b[j].second, nxt[sorted_b[j].second]);
j++;
}
// for (int k = 0; k < N; k++)
// cout << query(k, k) << " ";
// cout << "\n\n";
int qry = query(0, N - 1);
if (qry >= 0) {
cout << sorted_b[i].first - qry;
return 0;
}
}
// cout << sorted_b.back().first;
}
/*
2 15
9 1 14
9 5 1
*/
