Problem Statement

There are $N$ toys numbered from $1$ to $N$, and N−1 boxes numbered from 1 to N−1. Toy i (1≤i≤N) has a size of Ai, and box $i(1\le i\le N-1)$ has a size of Bi.

Takahashi wants to store all the toys in separate boxes, and he has decided to perform the following steps in order:

1. Choose an arbitrary positive integer $x$ and purchase one box of size $x$.

2. Place each of the $N$ toys into one of the $N$ boxes (the $N-1$ existing boxes plus the newly purchased box). Here, each toy can only be placed in a box whose size is not less than the toy's size, and no box can contain two or more toys.

He wants to execute step $2$ by purchasing a sufficiently large box in step $1$, but larger boxes are more expensive, so he wants to purchase the smallest possible box.

Determine whether there exists a value of $x$ such that he can execute step $2$, and if it exists, find the minimum such $x$.

Constraints

• $2\le N\le 2\times 10$

• $1\le A,B\le 10$

• All input values are integers.

Input

The input is given from Standard Input in the following format:

$N$$A$$A$$\dots$$A$$B$$B$$\dots$$B$

Output

If there exists a value of $x$ such that Takahashi can execute step $2$, print the minimum such $x$. Otherwise, print -1.

Sample Input 1

45 2 3 76 2 8

Sample Output 1

3

Consider the case where $x=3$ (that is, he purchases a box of size $3$ in step $1$).

If the newly purchased box is called box $4$, toys $1,\dots ,4$ have sizes of $5$, $2$, $3$, and $7$, respectively, and boxes $1,\dots ,4$ have sizes of $6$, $2$, $8$, and $3$, respectively. Thus, toy $1$ can be placed in box $1$, toy $2$ in box $2$, toy $3$ in box $4$, and toy $4$ in box $3$.

On the other hand, if $x\le 2$, it is impossible to place all $N$ toys into separate boxes. Therefore, the answer is $3$.

Sample Input 

43 7 2 58 1 6

Sample Output 

-1

No matter what size of box is purchased in step $1$, no toy can be placed in box $2$, so it is impossible to execute step $2$.

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排序处理，即可。如果装不下的话，就放到list中，如果list的size大于1了，说明一个盒子是不够的，所以输出-1即可。