/**
* author: Haunted_Cpp
**/
#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("Ofast")
#pragma GCC target("fma,sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#pragma GCC optimize("unroll-loops")
template<typename T> ostream &operator << (ostream &os, const vector<T> &v) { os << '{'; string sep; for (const auto &x : v) os << sep << x, sep = ", "; return os << '}'; }
template<typename T, size_t size> ostream &operator << (ostream &os, const array<T, size> &arr) { os << '{'; string sep; for (const auto &x : arr) os << sep << x, sep = ", "; return os << '}'; }
template<typename A, typename B> ostream &operator << (ostream &os, const pair<A, B> &p) { return os << '(' << p.first << ", " << p.second << ')'; }
void debug_out() { cerr << endl; }
template<typename Head, typename... Tail> void debug_out(Head H, Tail... T) { cerr << ' ' << H; debug_out(T...); }
#ifdef LOCAL
#define debug(...) cerr << "(" << #__VA_ARGS__ << "):", debug_out(__VA_ARGS__)
#else
#define debug(...) 47
#endif
class SegmentTree {
private:
struct Node {
long long prefix, sum, best;
Node () {
prefix = sum = best = 1e9;
}
void merge(Node l, Node r) {
prefix = min(l.prefix, l.sum + r.prefix);
sum = l.sum + r.sum;
best = min({l.best, prefix});
}
};
vector<Node> seg;
const int LO, HI;
void build(int l, int r, int node, const vector<int> &arr) {
if (l == r) {
seg[node].prefix = seg[node].sum = seg[node].best = arr[l];
return;
}
const int mid = l + (r - l) / 2;
build(l, mid, 2 * node + 1, arr);
build(mid + 1, r, 2 * node + 2, arr);
seg[node].merge(seg[2 * node + 1], seg[2 * node + 2]);
}
void modify(int where, int delta, int l, int r, int node) {
if (l > where || r < where) return;
if (l >= where && r <= where) {
seg[node].prefix = seg[node].sum = seg[node].best = delta;
return;
}
const int mid = l + (r - l) / 2;
modify(where, delta, l, mid, 2 * node + 1);
modify(where, delta, mid + 1, r, 2 * node + 2);
seg[node].merge(seg[2 * node + 1], seg[2 * node + 2]);
}
public:
SegmentTree(const vector<int> &arr) : LO(0), HI((int)arr.size() - 1) {
seg.clear();
seg.resize(4 * (int) arr.size());
build(LO, HI, 0, arr);
}
void modify(int where, int delta) {
modify(where, delta, LO, HI, 0);
}
long long worst_prefix() {
return seg[0].best;
}
};
int main () {
ios::sync_with_stdio(0);
cin.tie(0);
int n, d;
cin >> n >> d;
vector<tuple<int, int, int>> arr(n);
vector<pair<int, int>> top_up;
vector<int> distancias;
for (int i = 0; i < n; i++) {
int x, a, b;
cin >> x >> a >> b;
arr[i] = make_tuple(x, a, b);
distancias.emplace_back(x);
distancias.emplace_back(a);
distancias.emplace_back(b);
distancias.emplace_back(d - a);
distancias.emplace_back(d - b);
}
sort(arr.begin(), arr.end());
for (int i = 0; i < n; i++) top_up.emplace_back(get<2>(arr[i]), i);
sort(top_up.begin(), top_up.end());
vector<int> pre = {0};
vector<int> where_is_it(n);
long long s = 0;
for (int i = 0; i < n; i++) {
int dist = get<0>(arr[i]) - (i - 1 < 0 ? 0 : get<0>(arr[i - 1]));
s += dist;
distancias.emplace_back(max(0, dist - get<1>(arr[i - 1])));
distancias.emplace_back(s);
distancias.emplace_back(dist);
pre.emplace_back(-dist);
where_is_it[i] = pre.size();
pre.emplace_back(get<1>(arr[i]));
}
distancias.emplace_back(d - get<0>(arr.back()));
pre.emplace_back(-d + get<0>(arr.back()));
distancias.emplace_back(d);
sort(distancias.begin(), distancias.end());
distancias.erase(unique(distancias.begin(), distancias.end()), distancias.end());
SegmentTree seg(pre);
int rem = 0;
for (auto cur : distancias) {
debug("TEST: ", cur);
while(rem < n && get<0>(top_up[rem]) < cur) {
const int where = where_is_it[get<1>(top_up[rem])];
seg.modify(where, 0);
++rem;
}
seg.modify(0, cur);
if (seg.worst_prefix() >= 0) {
cout << cur << '\n';
return 0;
}
}
cout << "NO SOLUTION" << '\n';
return 0;
}
