import sys

def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]

def main():
    inf=10**16
    n,p=MI()
    abc=LLI(n)
    dp=[inf]*(p+1)
    dp[0]=0
    for rank in abc:
        rank.append(1)
        for i in range(p,-1,-1):
            dp[i]=min(dp[i-di]+rank[di] for di in range(4) if i-di>=0)

    print(dp[p]/n)

main()