#Lutece3329. Circuit

Circuit

Description

Cai1000 has nn resistors with a resistance of 1Ω1\Omega, and he wants to connect the nn resistors as follows:

  • Choose a resistor as the original circuit.
  • Perform the following operations n1n-1 times: Connect a resistor with a resistance of 1Ω1\Omega in series or parallel to the previous circuit.

Cai1000 wants to know the kk-th largest resistance value of the final circuit among all ways of connection (Two ways are considered different if and only if their resistance values are different). Cai1000 is very lazy, so he turned to you for help.

Two resistors with resistances R1R_1 and R2R_2 connected in series equal to a resistor with a resistance of R=R1+R2R=R_1+R_2.

Two resistors with resistances R1R_1 and R2R_2 connected in parallel equal to a resistor with a resistance of R=11R1+1R2R=\frac{1}{\frac{1}{R_1}+\frac{1}{R_2}}.

Input

One line with two integers nn (1n60)(1\leq n \leq 60) and kk (1k2n1)(1\leq k\leq 2^{n-1}).

Output

Print the kk-th largest resistance value which is expressed in the form of an irreducible fraction p/qp/q, i.e. pp and qq are integers which meet p,qZp,q\in \mathbb{Z} and gcd(p,q)=1\gcd(p,q)=1.

Samples

输入数据 1

3 3

输出数据 1

2/3

输入数据 2

4 3

输出数据 2

5/3

Note

In the first example, there are 44 ways of connection:

Their resistance values are 13,32,23,3\frac{1}{3},\frac{3}{2},\frac{2}{3},3 respectively. So the third largest resistance value is 23\frac{2}{3}.

Resources

电子科技大学第十四届 ACM 趣味程序设计竞赛