human
A New Year party is not a New Year party without lemonade! As usual, you are expecting a lot of guests, and buying lemonade has already become a pleasant necessity.

Your favorite store sells lemonade in bottles of n different volumes at different costs. A single bottle of type i has volume 2i - 1 liters and costs ci roubles. The number of bottles of each type in the store can be considered infinite.

You want to buy at least L liters of lemonade. How many roubles do you have to spend?

Input

The first line contains two integers n and L (1 ≤ n ≤ 30.
1 ≤ L ≤ 109) — the number of types of bottles in the store and the required amount of lemonade in liters, respectively.

The second line contains n integers c1, c2, ..., cn (1 ≤ ci ≤ 109) — the costs of bottles of different types.

Output

Output a single integer — the smallest number of roubles you have to pay in order to buy at least L liters of lemonade.

Examples

Input

4 12
20 30 70 90

Output

150

Input

4 3
10000 1000 100 10

Output

10

Input

4 3
10 100 1000 10000

Output

30

Input

5 787787787
123456789 234567890 345678901 456789012 987654321

Output

44981600785557577

Note

In the first example you should buy one 8-liter bottle for 90 roubles and two 2-liter bottles for 30 roubles each. In total you'll get 12 liters of lemonade for just 150 roubles.

In the second example, even though you need only 3 liters, it's cheaper to buy a single 8-liter bottle for 10 roubles.

In the third example it's best to buy three 1-liter bottles for 10 roubles each, getting three liters for 30 roubles.
# by 
=====
Give me a the Python code you requested?
assistant
#Here is the Python code you requested.
the authority of GOD   author: manhar singh sachdev #

import os,sys
from io import BytesIO,IOBase

def main():
    n,L = map(int,input().split())
    c = list(map(int,input().split()))
    for i in range(n-2,-1,-1):
        c[i] = min(c[i],c[i+1])
    for i in range(1,n):
        c[i] = min(c[i],2*c[i-1])
    while len(c) != 31:
        c.append(c[-1]*2)
    mask,su,ans,tk = 1<<30,0,float("inf"),0
    for i in range(30,-1,-1):
        if mask&L:
            z = L-tk
            ans = min(ans,su+c[z.bit_length()-(not z&z-1)])
            su += c[i]
            tk |= mask
        mask >>= 1
    print(ans)

# Fast IO Region
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 =...