#include<bits/stdc++.h>
using namespace std;
using i64 = long long;
int main(){
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];
// cout << e << " " << pref[i] << '\n';
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;
}
for(int i = 0;i < n;i++){
// f is between (b[i] to b[i + 1]];
int e = ind2[i];
int e2 = hs[e];
// removig b[e]
i64 my = 0;
for(int j = e2 + 1;j <= n;j++){
pref[j] -= a[e];
}
for(int j = 0;j <= n;j++){
my = max(my,-1LL * pref[j]);
}
if(b[e] < my && my <= (i + 1 < n ? b[ind2[i + 1]] : d)){
f = min(f,my);
}
}
cout << f << '\n';
return 0;
}
