You are given two binary strings $S$ and $T$ of the same length $N$. Your task is to make both the strings equal. Perform the following operation on string $S$:

Select any substring of $S$ then flip all 1's to 0 and flip all 0's to 1 of that substring.

Print the minimum number of operations you have to perform to make them equal.

Input format

• The first line contains a single integer $N$ ($1\le N\le 1e5$) size of each string
• The second line contains a string $S$ of length $N$. 
• The third line contains a string $T$ of length $N$. 

Output format

Print a single integer denoting the minimum number of operations required to make both the strings equal.

Constraints

$1\le N\le 1e5$