#include <bits/stdc++.h>

using namespace std;

int main()
{
  int N, P, A[5000][4];

  cin >> N >> P;
  for(int i = 0; i < N; i++) {
    cin >> A[i][0] >> A[i][1] >> A[i][2];
    A[i][3] = 1;
  }

  double dp1[15001], dp2[15001];
  fill_n(dp1, 15001, 1e9);
  dp1[0] = 0;
  for(int i = 0; i < N; i++) {
    fill_n(dp2, 15001, 1e9);
    for(int j = 15000; j >= 0; j--) {
      for(int k = 3; k >= 0; k--) {
        dp2[j + k] = min(dp2[j + k], dp1[j] + A[i][k]);
      }
    }
    swap(dp1, dp2);
  }

  cout << fixed << setprecision(10);
  cout << dp1[P] / N << endl;
}