Title
Problem Statement
We have a string X, which has an even number of characters. Half the characters are S, and the other half are T.
Takahashi, who hates the string ST, will perform the following operation 1010000 times:
- Among the occurrences of
ST in X as (contiguous) substrings, remove the leftmost one. If there is no occurrence, do nothing.
Find the eventual length of X.
Constraints
- 2 ≦ |X| ≦ 200,000
- The length of X is even.
- Half the characters in X are
S, and the other half are T.
Partial Scores
- In test cases worth 200 points, |X| ≦ 200.
Input
The input is given from Standard Input in the following format:
X
Output
Print the eventual length of X.
Sample Input 1
TSTTSS
Sample Output 1
4
In the 1-st operation, the 2-nd and 3-rd characters of TSTTSS are removed.
X becomes TTSS, and since it does not contain ST anymore, nothing is done in the remaining 1010000-1 operations.
Thus, the answer is 4.
Sample Input 2
SSTTST
Sample Output 2
0
X will eventually become an empty string: SSTTST ⇒ STST ⇒ ST ⇒ ``.
Sample Input 3
TSSTTTSS
Sample Output 3
4
X will become: TSSTTTSS ⇒ TSTTSS ⇒ TTSS.