You are given a string S of length N and another string T of length M. These strings consist of lowercase English letters.

A string X is called a good string when the following conditions are all met:

• Let L be the length of X. L is divisible by both N and M.
• Concatenating the $1-st, (\frac{L}{N}+1)-th, (2 \times \frac{L}{N}+1)-th, ..., ((N-1)\times\frac{L}{N}+1)-th$ characters of X, without changing the order, results in S.
• Concatenating the $1-st, (\frac{L}{M}+1)-th, (2 \times \frac{L}{M}+1)-th, ..., ((M-1)\times\frac{L}{M}+1)-th$ characters of X, without changing the order, results in T.

Determine if there exists a good string. If it exists, find the length of the shortest such string.

Constraints

• $1 \leq N,M \leq 10^5$
• S and T consist of lowercase English letters.
• |S|=N
• |T|=M

Input

Input is given from Standard Input in the following format:

N M
S
T

Output

If a good string does not exist, print -1; if it exists, print the length of the shortest such string.

Examples

Input

3 2
acp
ae

Output

6

Input

6 3
abcdef
abc

Output

-1

Input

15 9
dnsusrayukuaiia
dujrunuma

Output

45

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