#include <bits/stdc++.h>
using namespace std;
#define ll long long
const ll nx=3e5+5;
ll n, d, x[nx], a[nx], b[nx], t, cx[nx], rv[nx], res;
map<ll, vector<ll>> mp;
map<ll, ll> cmp;
struct segtree
{
ll mn[4*nx], lz[4*nx];
void build(int l, int r, int i)
{
if (l==r) return mn[i]=-rv[l], void();
int md=(l+r)/2;
build(l, md, 2*i);
build(md+1, r, 2*i+1);
mn[i]=min(mn[2*i], mn[2*i+1]);
}
void pushlz(int l, int r, int i)
{
mn[i]+=lz[i];
if (l!=r) lz[2*i]+=lz[i], lz[2*i+1]+=lz[i];
lz[i]=0;
}
void update(int l, int r, int i, int ql, int qr, int vl)
{
pushlz(l, r, i);
if (qr<l||r<ql||qr<ql) return;
if (ql<=l&&r<=qr) return lz[i]=vl, pushlz(l, r, i);
int md=(l+r)/2;
update(l, md, 2*i, ql, qr, vl);
update(md+1, r, 2*i+1, ql, qr, vl);
mn[i]=min(mn[2*i], mn[2*i+1]);
}
} s;
int main()
{
cin.tie(NULL)->sync_with_stdio(false);
cin>>n>>d;
for (int i=1; i<=n; i++) cin>>x[i]>>a[i]>>b[i], mp[b[i]].push_back(i), cmp[x[i]]=0;
cmp[d]=0;
for (auto &[x, y]:cmp) y=++t, rv[t]=x;
for (int i=1; i<=n; i++) cx[i]=cmp[x[i]];
s.build(1, t, 1);
res=d;
for (auto itr=mp.rbegin(); itr!=mp.rend(); itr++)
{
vector<ll> event=itr->second;
ll bound=itr->first;
for (auto idx:event) s.update(1, t, 1, cx[idx]+1, t, a[idx]);
if (s.mn[1]<=bound) res=min(res, -s.mn[1]);
}
cout<<res;
}
