#pragma region include
#include <iostream>
#include <iomanip>
#include <stdio.h>

#include <sstream>
#include <algorithm>
#include <cmath>
#include <complex>

#include <string>
#include <cstring>
#include <vector>
#include <tuple>

#include <queue>
#include <complex>
#include <set>
#include <map>
#include <stack>
#include <list>

#include <fstream>
#include <random>
//#include <time.h>
#include <ctime>
#pragma endregion //#include
/////////
#define REP(i, x, n) for(int i = x; i < n; ++i)
#define rep(i,n) REP(i,0,n)
/////////
#pragma region typedef
typedef long long LL;
typedef long double LD;
typedef unsigned long long ULL;
#pragma endregion //typedef
////定数
const int INF = (int)1e9;
const LL MOD = (LL)1e9+7;
const LL LINF = (LL)1e18;
const double PI = acos(-1.0);
const double EPS = 1e-9;
/////////
using namespace::std;

void solve(){
	//順位の和が最小値
	int N,P;
	cin >> N >> P;
	vector<LL> dp(P+1,INF);//index:正解数
	dp[0] = 0;
	for(int i=0;i<N;++i){
		int a,b,c;
		cin >> a >> b >> c;
		for(int pos=P;pos>=0;--pos){
			if( dp[pos] < INF ){
				if(pos+1 <= P )dp[pos+1] = min(dp[pos+1],dp[pos]+b);
				if(pos+2 <= P )dp[pos+2] = min(dp[pos+2],dp[pos]+c);
				if(pos+3 <= P )dp[pos+3] = min(dp[pos+3],dp[pos]+1);
				dp[pos] += a;
			}
		}
	}
	cout << (1.0*dp[P])/N << endl;
}

#pragma region main
signed main(void){
	std::cin.tie(0);
	std::ios::sync_with_stdio(false);
	std::cout << std::fixed;//小数を10進数表示
	cout << setprecision(16);//小数点以下の桁数を指定//coutとcerrで別	
	
	solve();
}
#pragma endregion //main()