Problem
Huckleberry Finn has two strings s and t of the same length n.
Huckleberry Finn likes strings to have the same prefixes (beginnings), so he can swap two characters in string s to make the common prefix of strings s and t larger.
However, this trick is rather tedious, so Huckleberry Finn will either not do it at all, or will do it exactly once.
Help Huckleberry Finn determine the longest common prefix length of strings s and t that he can get.
Input:
The first line contains a natural number n (1 <= n <= 200000) - the length of strings s and t
The second line contains a string s, consisting of lowercase Latin letters.
The third line contains a string t consisting of lowercase Latin letters.
Output:
Print one natural number - the maximum length of the common prefix s and t, which can be obtained by exchanging two characters in the string s at most once.
Examples:
| Input |
Output |
3
wai
add |
1 |
5
qdyid
xreac |
0 |