Fifty-Fifty

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

inputFormat

Input

Input is given from Standard Input in the following format:

S

outputFormat

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

样例

FFEE

Yes