Problem Statement

You are given an integer $N$ and $2$ strings $S, T$ of length $N$. Print the Hamming distance between $S$ and $T$.

Here, the Hamming distance between $S$ and $T$ is the number of indices $i$ ($1 \le i \le N$) such that the $i$-th character of $S$ and the $i$-th character of $T$ are different.

Constraints

• $1 \le N \le 100$.
• $N$ is an integer.
• $S, T$ are strings of length $N$ consisting of lowercase English letters.

Input

The input is given in the following format:

N
S
T

Output

Print the Hamming distance between $S$ and $T$.

Do not print anything other than the result. (Do not print sentences prompting for input, etc.)

For the answer format, you may also refer to the practice problems and their sample solutions.

Sample 1

Sample Input 1

3
joi
ioi

Sample Output 1

1

• The $1$-st characters of $S$ and $T$ are j and i, respectively, which are different.
• The $2$-nd characters of $S$ and $T$ are o and o, respectively, which match.
• The $3$-rd characters of $S$ and $T$ are i and i, respectively, which match.
• Therefore, since the Hamming distance between joi and ioi is $1$, print $1$.

Sample 2

Sample Input 2

5
march
april

Sample Output 2

4

• Since the Hamming distance between march and april is $4$, print $4$.

Sample 3

Sample Input 3

6
sample
sample

Sample Output 3

0

• Since the Hamming distance between sample and sample is $0$, print $0$.