//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#define rep(i, n) for(int i=0; i<n; ++i)
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
using namespace std;
using ll = int64_t;
using ld = long double;
using P = pair<int, int>;
using vs = vector<string>;
using vi = vector<int>;
using vvi = vector<vi>;
template<class T> using PQ = priority_queue<T>;
template<class T> using PQG = priority_queue<T, vector<T>, greater<T> >;
const int INF = 100010001;
const ll LINF = (ll)INF*INF*10;
template<typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {return a < b && (a = b, true);}
template<typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {return a > b && (a = b, true);}
template<typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) { return is >> p.first >> p.second;}
template<typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) { return os << p.first << ' ' << p.second;}

const int N = 5010;
const int Z = N*3;

//head

int n, p;
int place[N][4];
int dp[Z];

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin >> n >> p;
	rep(i, n) {
		int a, b, c;
		cin >> a >> b >> c;
		place[i][0] = a;
		place[i][1] = b;
		place[i][2] = c;
		place[i][3] = 1;
	}

	fill(dp+1, dp+p+1, 0x7f0fffff);
	rep(i, n) {
		for(int j = p; j >= 0; j--) {
			dp[j] += place[i][0];
			rep(k, min(3, j)) chmin(dp[j], dp[j-k-1]+place[i][k+1]);
		}
	}

	cout << fixed << setprecision(20) << (ld)dp[p]/n << endl;
}