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.
import java.io.*;
import java.util.*;
import java.math.*;

public class utkarsh {

    InputStream is;
    PrintWriter out;
    
    long maxl = (long) 4e18, mod = (long)1e9 + 7L;
    
    class pair {
        double F;
        int I;
        pair(double x, int y) {
            F = x;
            I = y;
        }
    }
    
    int n;
    long d[];
    HashMap <Integer, Long> mp = new HashMap<>();
    
    long play(int l) {
        if(l <= 0)  return 0;
        if(mp.containsKey(l)) return mp.get(l);
        long x, y, ans = maxl;
        for(int i = 0; i < n; i++) {
            int j = (1 << i);
            x = y = maxl;
            if(l >= j) x = d[i] * (l / j) + play(l % j);
            if(l % j != 0)  y = d[i] * (l / j) + d[i];
            if(y < x)   x = y;
            if(x < ans) ans = x;
        }
        mp.put(l, ans);
        return ans;
    }
    
    void solve(){
        //Enter code here utkarsh
        n = ni();
        int l = ni();
        d = new long[n];
        for(int i = 0; i < n; i++) {
            d[i] = nl();
        }
        long ans = play(l);
        out.println(ans);
    }
    
    long modpow(long base, long exp, long modulus) { base %= modulus; long result = 1L; while (exp > 0) { if ((exp & 1)==1) result = (result * base) % modulus; base = (base * base) % modulus; exp >>= 1; } return result;
    }
    
    public static void main(String[] args) { new utkarsh().run();
    }
    void run(){ is = System.in; out = new PrintWriter(System.out); solve(); out.flush();
    }
    
    byte input[] = new byte[1024];
    int len = 0, ptr = 0;
    
    int readByte(){ if(ptr >= len){ ptr = 0; try{ len = is.read(input); }catch(IOException e){ throw new InputMismatchException(); } if(len <= 0){ return -1; } } return input[ptr++];
    }
    boolean isSpaceChar(int c){ return !( c >= 33 && c <= 126 ); 
    }
    int skip(){ int b = readByte(); while(b != -1 && isSpaceChar(b)){ b = readByte(); } return b;
    }
    
    char nc(){ return (char)skip();
    }
    String ns(){ int b = skip(); StringBuilder sb = new StringBuilder(); while(!isSpaceChar(b)){ sb.appendCodePoint(b); b=readByte(); } return sb.toString();
    }
    int ni(){ int n = 0,b = readByte(); boolean minus = false; while(b != -1 && !( (b >= '0' && b <= '9') || b == '-')){ b = readByte(); } if(b == '-'){ minus = true; b = readByte(); } if(b == -1){ return -1; } while(b >= '0' && b <= '9'){ n = n * 10 + (b - '0'); b = readByte(); } return minus ? -n : n;
    }
    long nl(){ long n = 0L; int b = readByte(); boolean minus = false; while(b != -1 && !( (b >= '0' && b <= '9') || b == '-')){ b = readByte(); } if(b == '-'){ minus = true; b = readByte(); } while(b >= '0' && b <= '9'){ n = n * 10 + (b - '0'); b = readByte(); } return minus ? -n : n;
    }
    double nd(){ return Double.parseDouble(ns());
    }
    float nf(){ return Float.parseFloat(ns());
    }
    int[] na(int n){ int a[] = new int[n]; for(int i = 0; i < n; i++){ a[i] = ni(); } return a;
    }
    char[] ns(int n){ char c[] = new char[n]; int i,b = skip(); for(i = 0; i < n; i++){ if(isSpaceChar(b)){ break; } c[i] = (char)b; b = readByte(); } return i == n ? c : Arrays.copyOf(c,i);
    }
}