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

const int N = 5e5 + 10;

double x[N], rd[N]{1}, v[N], f[N];
int q[N], tail, head;
int id[N], tmp[N];

double Y (int i) { return f[i] - x[i] * sqrt(rd[i]) / (rd[i] * 2); }
double X (int i) { return sqrt(rd[i]) / rd[i]; }
double slope_up (int i, int j) { return Y(i) - Y(j); }
double slope_down (int i, int j) { return X(i) - X(j); }

void dvd (int l, int r) {
	if (l == r) return ;
	int mid = (l + r) >> 1;
	dvd (l, mid);
	
	head = tail = 0;
	q[head] = 0;
	for (int i = l; i <= mid; i++) {
		while (head < tail && slope_up(q[tail], q[tail - 1]) * slope_down(id[i], q[tail]) >= slope_up(id[i], q[tail]) * slope_down(q[tail], q[tail - 1])) tail--;
		q[++tail] = id[i];
	}
	
	for (int i = r; i > mid; i--) {
		while (head < tail && slope_up(q[head + 1], q[head]) <= (-x[id[i]] / 2) * slope_down(q[head + 1], q[head])) head++;
		int j = q[head];
		f[id[i]] = min(f[id[i]], f[j] + v[id[i]] + (x[id[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;
	}
	
	for (int i = 0; i <= n; i++) f[i] = 1e14;
	f[id[1]] = v[id[1]];
	
	dvd (1, n);
	
	double ans = 1e14;
	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;
}