#include <bits/stdc++.h>
using namespace std;
template <class T>
inline void read(T &x) {
  x = 0;
  char c = getchar();
  int f = 1;
  while (!isdigit(c)) {
    if (c == '-') f = -1;
    c = getchar();
  }
  while (isdigit(c)) {
    x = x * 10 + c - '0';
    c = getchar();
  }
  x *= f;
}
template <class T>
inline void umin(T &x, T y) {
  x = x < y ? x : y;
}
template <class T>
inline void umax(T &x, T y) {
  x = x > y ? x : y;
}
inline unsigned int R() {
  static unsigned int seed = 416;
  return seed ^= seed >> 5, seed ^= seed << 17, seed ^= seed >> 13;
}
const int N = 266666;
int n, id[N];
double lim, a[N], b[N], c[N], res, E, cost[N], v_space[N], v_line[N],
    val[N << 2], lzy[N << 2], mn[N];
int len;
bool cmp(int x, int y) { return c[x] < c[y]; }
void space(double x) {
  if (E >= x / 2) {
    E -= x / 2;
    res += x / 2;
    v_space[++len] = 2;
  } else {
    double v = x / (x - E);
    E = 0;
    res += x / v;
    v_space[++len] = v;
  }
}
void upd(int k) { val[k] = min(val[k << 1], val[k << 1 | 1]); }
void pushdown(int k) {
  if (lzy[k]) {
    lzy[k << 1] += lzy[k];
    val[k << 1] += lzy[k];
    lzy[k << 1 | 1] += lzy[k];
    val[k << 1 | 1] += lzy[k];
    lzy[k] = 0;
  }
}
void add(int k, int l, int r, double x, int L, int R) {
  if (l == L && r == R) {
    val[k] += x;
    lzy[k] += x;
    return;
  }
  int mid = (L + R) >> 1;
  pushdown(k);
  if (r <= mid)
    add(k << 1, l, r, x, L, mid);
  else if (l > mid)
    add(k << 1 | 1, l, r, x, mid + 1, R);
  else
    add(k << 1, l, mid, x, L, mid), add(k << 1 | 1, mid + 1, r, x, mid + 1, R);
  upd(k);
}
double qry(int k, int l, int r, int L, int R) {
  if (l == L && r == R) return val[k];
  int mid = (L + R) >> 1;
  pushdown(k);
  if (r <= mid)
    return qry(k << 1, l, r, L, mid);
  else if (l > mid)
    return qry(k << 1 | 1, l, r, mid + 1, R);
  return min(qry(k << 1, l, mid, L, mid),
             qry(k << 1 | 1, mid + 1, r, mid + 1, R));
}
void ck(double x, double c, double v) {
  E -= x - (c + 1) * x / (v + c);
  cerr << "E=" << E << endl;
  assert(E >= -1e-8);
}
int main() {
  read(n);
  scanf("%lf", &lim);
  for (register int i = (1); i <= (n); i++)
    scanf("%lf%lf%lf", &a[i], &b[i], &c[i]);
  for (register int i = (1); i <= (n); i++) mn[i] = 1e18;
  for (register int i = (1); i <= (n); i++) {
    space(a[i] - b[i - 1]);
    umin(mn[i - 1], E);
    E += (b[i] - a[i]) / c[i];
    cost[i] = (b[i] - a[i]) / c[i];
    umin(mn[i], E);
  }
  space(lim - b[n]);
  umin(mn[n], E);
  for (register int i = (1); i <= (n); i++) add(1, i, i, mn[i], 1, n);
  for (register int i = (1); i <= (n); i++) id[i] = i;
  sort(id + 1, id + n + 1, cmp);
  for (register int tt = (1); tt <= (n); tt++) {
    int i = id[tt];
    double E = qry(1, i, n, 1, n) - (b[i] - a[i]) / c[i];
    add(1, i, n, -(b[i] - a[i]) / c[i], 1, n);
    if ((b[i] - a[i]) / (2 + c[i]) <= E) {
      add(1, i, n, -(b[i] - a[i]) / (2 + c[i]), 1, n);
      cost[i] = (b[i] - a[i]) / (2 + c[i]);
      v_line[i] = 2;
    } else {
      assert(b[i] - a[i] - E != 0);
      double v = (c[i] + 1) * (b[i] - a[i]) / (b[i] - a[i] - E) - c[i];
      add(1, i, n, -E, 1, n);
      cost[i] = (b[i] - a[i]) / (v + c[i]);
      E = 0;
      v_line[i] = v;
    }
  }
  for (register int i = (1); i <= (n); i++) res += cost[i];
  printf("%.11lf\n", res);
  return 0;
}
