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What is a Python code to find a way to conduct all the songs of the Devu, output -1 given the following:
Devu is a renowned classical singer. He is invited to many big functions/festivals. Recently he was invited to "All World Classical Singing Festival". Other than Devu, comedian Churu was also invited.

Devu has provided organizers a list of the songs and required time for singing them. He will sing n songs, ith song will take ti minutes exactly. 

The Comedian, Churu will crack jokes. All his jokes are of 5 minutes exactly.

People have mainly come to listen Devu. But you know that he needs rest of 10 minutes after each song. On the other hand, Churu being a very active person, doesn't need any rest.

You as one of the organizers should make an optimal sсhedule for the event. For some reasons you must follow the conditions:

  * The duration of the event must be no more than d minutes.

  * Devu must complete all his songs.

  * With satisfying the two previous conditions the number of jokes cracked by Churu should be as many as possible. 


If it is not possible to find a way to conduct all the songs of the Devu, output -1. Otherwise find out maximum number of jokes that Churu can crack in the grand event.

Input

The first line contains two space separated integers n, d (1 ≤ n ≤ 100.
1 ≤ d ≤ 10000). The second line contains n space-separated integers: t1, t2, ..., tn (1 ≤ ti ≤ 100).

Output

If there is no way to conduct all the songs of Devu, output -1. Otherwise output the maximum number of jokes that Churu can crack in the grand event.

Examples

Input

3 30
2 2 1

Output

5

Input

3 20
2 1 1

Output

-1

Note

Consider the first example. The duration of the event is 30 minutes. There could be maximum 5 jokes in the following way:

  * First Churu cracks a joke in 5 minutes. 
  * Then Devu performs the first song for 2 minutes. 
  * Then Churu cracks 2 jokes in 10 minutes. 
  * Now Devu performs second song for 2 minutes. 
  * Then Churu cracks 2 jokes in 10 minutes. 
  * Now finally Devu will perform his last song in 1 minutes. 


Total time spent is 5 + 2 + 10 + 2 + 10 + 1 = 30 minutes.

Consider...
The above is tricky. Write me a correct solution in PYTHON3.
assistant
#Here is Python code to find a way to conduct all the songs of the Devu, output -1.

'''

* Author : Ayushman Chahar #
* About  : IT Sophomore    #
* Insti  : VIT, Vellore    #

'''

import os
import sys
# from collections import *
# from itertools import *
# from math import *
# from queue import *
# from heapq import *
# from bisect import *
from io import BytesIO, IOBase

BUFSIZE = 8192

class FastIO(IOBase):
    newlines = 0

    def __init__(self, file):
        self._fd = file.fileno()
        self.buffer = BytesIO()
        self.writable = "x" in file.mode or "r" not in file.mode
        self.write = self.buffer.write if self.writable else None

    def read(self):
        while True:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            if not b:
                break
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines = 0
        return self.buffer.read()

    def readline(self):
        while self.newlines == 0:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            self.newlines = b.count(b"\n") + (not b)
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines -= 1
        return self.buffer.readline()

    def flush(self):
        if self.writable:
            os.write(self._fd, self.buffer.getvalue())
            self.buffer.truncate(0), self.buffer.seek(0)

class IOWrapper(IOBase):
    def __init__(self, file):
        self.buffer = FastIO(file)
        self.flush = self.buffer.flush
        self.writable = self.buffer.writable
        self.write = lambda s: self.buffer.write(s.encode("ascii"))
        self.read = lambda: self.buffer.read().decode("ascii")
        self.readline = lambda: self.buffer.readline().decode("ascii")

sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda: sys.stdin.readline().rstrip("\r\n")
readint = lambda: int(sys.stdin.readline().rstrip("\r\n"))
readints = lambda: map(int,...