#include<bits/stdc++.h>
using namespace std;
using i64 = long long;
const int N = 3e5 + 1;
vector<i64> tree(4 * N,0);
vector<i64> lazy(4 * N,0);
void build(int ind,int nl,int nr,vector<i64> &pref){
if(nl == nr){
tree[ind] = pref[nl];
}else{
int mid = (nl + nr) / 2;
build(2 * ind,nl,mid,pref);
build(2 * ind + 1,mid + 1,nr,pref);
tree[ind] = min(tree[2 * ind],tree[2 * ind + 1]);
}
}
void dolazy(int ind){
tree[2 * ind] += lazy[ind];
tree[2 * ind + 1] += lazy[ind];
lazy[2 * ind] += lazy[ind];
lazy[2 * ind + 1] += lazy[ind];
lazy[ind] = 0;
}
void update(int ind,int nl,int nr,int l,int r,int v){
if(nl > r || l > nr) return;
if(l <= nl && nr <= r){
tree[ind] -= v;
lazy[ind] -= v;
return;
}
int mid = (nl + nr) / 2;
dolazy(ind);
update(2 * ind,nl,mid,l,r,v);
update(2 * ind + 1,mid + 1,nr,l,r,v);
tree[ind] = min(tree[2 * ind],tree[2 * ind + 1]);
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n,d;
cin >> n >> d;
vector<int> x(n),a(n),b(n);
for(int i = 0;i < n;i++){
cin >> x[i] >> a[i] >> b[i];
}
vector<int> ind(n);
iota(ind.begin(),ind.end(),0);
sort(ind.begin(),ind.end(),[&](int i,int j){
return x[i] < x[j];
});
vector<int> ind2(n);
iota(ind2.begin(),ind2.end(),0);
sort(ind2.begin(),ind2.end(),[&](int i,int j){
return b[i] < b[j];
});
vector<i64> pref(n + 1);
i64 tot = 0;
vector<int> hs(n);
for(int i = 0;i < n;i++){
int e = ind[i];
hs[e] = i;
if(i) pref[i] = pref[i - 1] - (x[e] - x[ind[i - 1]]) + a[ind[i - 1]];
else pref[i] = -x[e];
tot = max(tot,-1LL * pref[i]);
}
pref[n] = pref[n - 1] - (d - x[ind[n - 1]]) + a[ind[n - 1]];
tot = max(tot,-1LL * pref[n]);
i64 f = d;
if(tot <= b[ind2[0]]){
f = tot;
cout << f << '\n';
exit(0);
}
build(1,0,n,pref);
for(int i = 0;i < n;i++){
// f is between (b[i] to b[i + 1]];
int e = ind2[i];
int e2 = hs[e];
i64 my = 0;
update(1,0,n,e2 + 1,n,a[e]);
my = -1LL * tree[1];
if(b[e] < my && my <= (i + 1 < n ? b[ind2[i + 1]] : d)){
f = min(f,my);
break;
}
}
cout << f << '\n';
return 0;
}
