p02987 AtCoder Beginner Contest 132 - 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
```python
print("Yes" if len(set(input())) == 2 else "No")
```