You are given a 4-character string S consisting of uppercase English letters. Determine if S consists of exactly two kinds of characters which both appear twice in S.

Constraints

• The length of S is 4.
• S consists of uppercase English letters.

Input

Input is given from Standard Input in the following format:

S

Output

If S consists of exactly two kinds of characters which both appear twice in S, print Yes; otherwise, print No.

Examples

Input

ASSA

Output

Yes

Input

STOP

Output

No

Input

FFEE

Output

Yes

Input

FREE

Output

No

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