#include <cstdio>
#include <algorithm>
#pragma warning(disable : 4996)
using namespace std;
int n, p, a[5009], b[5009], c[5009], dp[15009];
int main() {
	scanf("%d%d", &n, &p);
	for (int i = 0; i < n; i++) scanf("%d%d%d", &a[i], &b[i], &c[i]);
	fill(dp + 1, dp + p + 1, 999999999);
	for (int i = 0; i < n; i++) {
		for (int j = min(3 * i, p); j >= 0; j--) {
			dp[j + 3] = min(dp[j + 3], dp[j] + 1);
			dp[j + 2] = min(dp[j + 2], dp[j] + c[i]);
			dp[j + 1] = min(dp[j + 1], dp[j] + b[i]);
			dp[j] += a[i];
		}
	}
	printf("%.9lf\n", 1.0 * dp[p] / n);
	return 0;
}