#include <bits/stdc++.h>
#define fo(i, d, c) for (int i = d; i <= c; i++)
#define fod(i, c, d) for (int i = c; i >= d; i--)
#define maxn 1000010
#define N 1010
#define fi first
#define se second
#define pb emplace_back
#define en cout << "\n";
#define int long long
#define inf (int)1e18
#define pii pair<int, int>
#define vii vector<pii>
#define lb(x) x & -x
#define bit(i, j) ((i >> j) & 1)
#define offbit(i, j) (i ^ (1LL << j))
#define onbit(i, j) (i | (1LL << j))
#define vi vector<int>
#define all(x) x.begin(), x.end()
template <typename T1, typename T2>
bool minimize(T1 &a, T2 b)
{
if (a > b)
{
a = b;
return true;
}
return false;
}
template <typename T1, typename T2>
bool maximize(T1 &a, T2 b)
{
if (a < b)
{
a = b;
return true;
}
return false;
}
using namespace std;
const int nsqrt = 450;
const int mod = 1e9 + 7;
struct SegmentTree
{
vector<int> st, lazy;
int n;
/// real n
SegmentTree(int _n = 0) : n(_n)
{
st.resize(4 * n + 10);
lazy.resize(4 * n + 10);
}
void resize(int _n)
{
n = _n;
st.resize(4 * n + 10);
lazy.resize(4 * n + 10);
}
void down(int id, int l, int r)
{
st[id << 1] += lazy[id];
lazy[id << 1] += lazy[id];
st[id << 1 | 1] += lazy[id];
lazy[id << 1 | 1] += lazy[id];
lazy[id] = 0;
}
void update(int id, int l, int r, int u, int v, int val)
{
if (u > r || l > v)
return;
if (u <= l && r <= v)
{
st[id] += val;
lazy[id] += val;
return;
}
down(id, l, r);
int mid = (l + r) >> 1;
update(id << 1, l, mid, u, v, val);
update(id << 1 | 1, mid + 1, r, u, v, val);
st[id] = max(st[id << 1], st[id << 1 | 1]);
}
int get(int id, int l, int r, int u, int v)
{
if (l > v || u > r)
return -inf;
if (u <= l && r <= v)
return st[id];
down(id, l, r);
int mid = (l + r) >> 1;
return max(get(id << 1, l, mid, u, v), get(id << 1 | 1, mid + 1, r, u, v));
}
int walkright(int id, int l, int r, int x, int val)
{
if (st[id] <= val)
return -1;
if (r < x)
return -1;
if (l == r)
return l;
int ans = -1;
int mid = (l + r) >> 1;
if (st[id << 1] > val)
ans = walkright(id << 1, l, mid, x, val);
if (ans == -1)
ans = walkright(id << 1 | 1, mid + 1, r, x, val);
return ans;
}
int walkleft(int id, int l, int r, int x, int val)
{
if (st[id] <= val)
return -1;
if (x < l)
return -1;
if (l == r)
return l;
int ans = -1;
int mid = (l + r) >> 1;
if (st[id << 1 | 1] > val)
ans = walkleft(id << 1 | 1, mid + 1, r, x, val);
if (ans == -1)
ans = walkleft(id << 1, l, mid, x, val);
return ans;
}
int get(int l, int r)
{
return get(1, 1, n, l, r);
}
void update(int l, int r, int val)
{
update(1, 1, n, l, r, val);
}
};
int n;
vii ke[maxn];
vi nen;
array<int,3> a[maxn];
main()
{
#define name "TASK"
if (fopen(name ".inp", "r"))
{
freopen(name ".inp", "r", stdin);
freopen(name ".out", "w", stdout);
}
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int d;
cin >> n >> d;
fo(i, 1, n)
{
cin >> a[i][0] >> a[i][1] >> a[i][2];
nen.pb(a[i][0]);
}
nen.pb(d);
sort(all(nen));
nen.erase(unique(all(nen)),nen.end());
int sz = (int)nen.size();
SegmentTree st(sz);
fo(i,1,sz) st.update(i,i,nen[i - 1]);
fo(i,1,n) a[i][0] = lower_bound(all(nen),a[i][0]) - nen.begin() + 1;
sort(a + 1,a + n + 1,[](array<int,3> a,array<int,3> b)
{
return a[2] > b[2] or (a[2] == b[2] and a[0] > b[0]);
});
int ans = d;
fo(i,1,n)
{
st.update(a[i][0] + 1,sz,-a[i][1]);
if(max(st.get(1,sz),0LL) <= a[i][2]) minimize(ans,max(st.get(1,sz),0LL));
}
cout << ans;
}
