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.

Input

Input is given from Standard Input in the following format:
S
T

Output

Print the answer.

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.

Sample Input 1

cupofcoffee
cupofhottea

Sample Output 1

4

We can achieve the objective in four operations, such as the following:

• First, replace the sixth character c with h.
• Second, replace the eighth character f with t.
• Third, replace the ninth character f with t.
• Fourth, replace the eleventh character e with a.

Sample Input 2

abcde
bcdea

Sample Output 2

5

Sample Input 3

apple
apple

Sample Output 3

0

No operations may be needed to achieve the objective.

见题面 Input 部分

见题面 Output 部分