Problem Statement

Given are strings $S$ and $T$. Consider changing $S$ to $T$ by repeating the operation below. Find the minimum number of operations required to do so.

Operation: Choose one character of $S$ and replace it with a different character.

Constraints

• $S$ and $T$ have lengths between $1$ and $2\times 10^5$ (inclusive).
• $S$ and $T$ consists of lowercase English letters.
• $S$ and $T$ have equal lengths.

Input

Input is given from Standard Input in the following format:

S
T

Output

Print the answer.