Three Different Letters

Problem Description

Write a function that accepts two strings and returns true if they are identical in length but have no more than three different letters, taking case and string order into account.

Input

• Two strings.

Output

• A boolean value: true if the strings are identical in length but have no more than three different letters, false otherwise.

Constraints

• The function should take case and string order into account.
• Both strings must be of the same length to be considered.

Example

Input:
"Clamp"
"Cramp"

Output:
true

Explanation:
The strings "Clamp" and "Cramp" have the same length and only one different letter ('l' in "Clamp" and 'r' in "Cramp").

Input:
"Clamp"
"Crams"

Output:
true

Explanation:
The strings "Clamp" and "Crams" have the same length and exactly three different letters ('l', 'p' in "Clamp" and 'r', 's' in "Crams").

Input:
"Clamp"
"Grams"

Output:
true

Explanation:
The strings "Clamp" and "Grams" have the same length and exactly three different letters ('C', 'l', 'p' in "Clamp" and 'G', 'r', 's' in "Grams").

Input:
"Clamp"
"Grans"

Output:
false

Explanation:
The strings "Clamp" and "Grans" have more than three different letters.

Input:
"Clamp"
"Clam"

Output:
false

Explanation:
The strings "Clamp" and "Clam" do not have the same length.

Input:
"clamp"
"maple"

Output:
false

Explanation:
The strings "clamp" and "maple" have more than three different letters and do not meet the criteria.