#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define f first
#define s second
#define pb push_back
#define ep emplace
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define uniquev(v) sort(all(v)), (v).resize(unique(all(v)) - (v).begin())
#define mem(f,x) memset(f , x , sizeof(f))
#define sz(x) (ll)(x).size()
#define __lcm(a, b) (1ll * ((a) / __gcd((a), (b))) * (b))
#define mxx *max_element
#define mnn *min_element
#define cntbit(x) __builtin_popcountll(x)
#define len(x) (int)(x.length())
const int N = 3e5 + 10;
ll seg[N * 4], laz[N * 4];
void push(int id) {
ll t = laz[id];
laz[id * 2] += t;
laz[id * 2 + 1] += t;
seg[id * 2] += t;
seg[id * 2 + 1] += t;
laz[id] = 0;
}
void upd(int id, int l, int r, int u, int v, ll add) {
if (l > v || r < u)
return;
if (l >= u && r <= v) {
seg[id] += add;
laz[id] += add;
return;
}
push(id);
int m = (l + r) / 2;
upd(id * 2, l, m, u, v, add);
upd(id * 2 + 1, m + 1, r, u, v, add);
seg[id] = min(seg[id * 2], seg[id * 2 + 1]);
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n, d;
cin >> n >> d;
vector <int> pos;
vector < vector <int>> station;
for (int i = 1; i <= n; i++) {
int x, a, b;
cin >> x >> a >> b;
station.pb({b, x, a});
pos.pb(x);
}
pos.pb(0);
pos.pb(d);
uniquev(pos);
sort(all(station), greater <vector <int>> ());
for (int i = 0; i < sz(pos); i++) {
upd(1, 0, sz(pos) - 1, i, i, -pos[i]);
}
int ans = d;
for (auto x : station) {
int p = upper_bound(all(pos), x[1]) - pos.begin();
upd(1, 0, sz(pos) - 1, p, sz(pos) - 1, x[2]);
if (abs(seg[1]) <= x[0]) {
ans = min(ans, (int)abs(seg[1]));
}
}
cout << ans << '\n';
return 0;
}
