#include <bits/stdc++.h>
using namespace std;

const int N = 5e6 + 10;

double x[N], rd[N], v[N], f[N], X[N], Y[N];
int q[N], tail;
int id[N], tmp[N];

double slope (int i, int j) { return (Y[i] - Y[j]) / (X[i] - X[j]); }

void dvd (int l, int r) {
	if (l == r) {
		Y[l] = f[l] - x[l] * sqrt(rd[l]) / (rd[l] * 2);
		return ;
	}
	int mid = (l + r) >> 1;
	dvd (l, mid);
	
	tail = 0;
	for (int i = l; i <= mid; i++) {
		while (tail > 1 && slope(q[tail], q[tail - 1]) >= slope(id[i], q[tail])) tail--;
		q[++tail] = id[i];
	}
	for (int i = mid + 1; i <= r; i++) {
		while (tail > 1 && slope(q[tail], q[tail - 1]) >= -x[i] / 2) tail--;
		int j = q[tail];
		f[i] = min(f[i], f[j] + v[i] + (x[i] - x[j]) / (sqrt(rd[j]) * 2));
	}
	
	dvd (mid + 1, r); 
	
	int p1 = l, p2 = mid + 1, pk = l;
	while (p1 <= mid || p2 <= r) {
		if (p2 > r || (p1 <= mid && X[id[p1]] <= X[id[p2]])) tmp[pk++] = id[p1++];
		else tmp[pk++] = id[p2++];
	}
	for (int i = l; i <= r; i++) id[i] = tmp[i];
}

void solve() {
	int n;
	double m;
	cin >> n >> m;
	for (int i = 1; i <= n; i++) {
		cin >> x[i] >> rd[i] >> v[i];
		if (rd[i] == 0) { --i; --n; continue ; }
		id[i] = i;
		X[i] = sqrt(rd[i]) / rd[i];
	}
	
	for (int i = 0; i <= n; i++) f[i] = 1e16;
	f[1] = v[1];
	
	dvd (1, n);
	
	double ans = 1e16;
	for (int i = 1; i <= n; i++) {
		if (x[i] + rd[i] >= m) ans = min(ans, f[i]);
	}
	printf("%.3lf", ans);
}

signed main() {
	ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
	solve();
	return 0;
}