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.

Examples

Input

cupofcoffee
cupofhottea

Output

4

Input

abcde
bcdea

Output

5

Input

apple
apple

Output

0

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