#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MOD = 1000000007;
const int MAX_N = 15010;
const int INF = 1<<29;

#define REP(i,n) for((i)=0;(i)<(int)(n);(i)++)

int a[MAX_N][3];
int dp[MAX_N];
double ans;

int main(){
    int n, p;
    cin >> n >> p;
    for (int i = 0; i < n; i++) cin >> a[i][0] >> a[i][1] >> a[i][2];

    for (int j = 0; j < MAX_N; j++) dp[j] = INF;
    dp[0] = 0;

    for(int i = 0; i < n; i++){
        for (int j = p; j >= 0; j--){
            dp[j] += a[i][0];
            for (int k = 1; k < 3; k++){
                if (j - k >= 0) dp[j] = min(dp[j], dp[j - k] + a[i][k]);
            }
            if (j - 3 >= 0) dp[j] = min(dp[j], dp[j - 3] + 1);
        }
    }

    ans = 1.0 * dp[p] / n;

    cout << ans << endl;    

    return 0;
}