Given two strings S and T, find length of the shortest subsequence in S which is not a subsequence in T. If no such subsequence is possible, return -1. A subsequence is a sequence that appears in the same relative order, but not necessarily contiguous. A string of length n has different possible subsequences.

**Input:**

The first line of input contains an integer T denoting the number of test cases. Then T test cases follow. The first line of each test case contains integers M and N where M denotes the length of first string and N denotes the length of second string.

The second line of each test case contains the two string S and T. Both string are comprised only of lower case alphabets.

**Output:**

Output the length of the shortest uncommon subsequence for each test case in a new line. If no such sub sequence is possible print -1.

**Constraints:**

1<= T <=100

1<= N,M <=500

**Example:**

**Input:**

1

5 5

babab babba

**Output:**

3

Ibrahim Nash | 77 |

Stark_Maverick | 68 |

wmlam | 54 |

Lam Ngoc Pham | 50 |

Micky_Kt | 48 |

Lam Ngoc Pham | 455 |

All Is Well | 399 |

Divvya Sinha | 374 |

Prateek Gole | 363 |

ioan | 319 |

akhayrutdinov | 3855 |

sanjay05 | 3366 |

Michael Riegger | 2023 |

Jasleen Kaur 2 | 2012 |

Quandray | 1965 |