**Description:**
Given two numeric strings $s$ and $t$ of length $n$. You construct a number from $s$ by processing its digits from left to right (from $s[1]$ to $s[n]$). For each digit, you can append it either to the **left** or to the **right** of the number currently formed.
**Task**: Find the smallest number $\ge t$ that can be created. If no such number exists, output -1.
#### Input
- The first line contains $T$ ($1 \le T \le 500$), the number of test cases.
- For each test case:
- First line contains $n$ ($1 \le n \le 500$).
- Second line contains string $s$.
- Third line contains string $t$.
- It is guaranteed that the sum of $n$ over $T$ test cases does not exceed $500$.
#### Output
- For each test case, print the result on a new line.
#### Example
Input:
```
2
3
123
200
4
4321
1234
```
Output:
```
213
1234
```
#### Subtasks
- **Subtask 1 (20 points)**: $n \le 16$.
- **Subtask 2 (60 points)**: $n \le 100$.
- **Subtask 3 (20 points)**: No additional constraints.
