Problem 550A - Two Substrings

A - Two Substrings

You are given string s. Your task is to determine if the given strings contains two non-overlapping substrings "AB" and "BA" (the substrings can go in any order).

Input

The only line of input contains a string s of length between1 and 105 consisting of uppercase Latin letters.

Output

Print "YES" (without the quotes), if strings contains two non-overlapping substrings "AB" and "BA", and "NO" otherwise.

Example

INPUT

ABA

OUTPUT

NO

INPUT

BACFAB

OUTPUT

YES

INPUT

AXBYBXA

OUTPUT

NO

Note

In the first sample test, despite the fact that there are substrings "AB" and "BA", their occurrences overlap, so the answer is "NO".

In the second sample test there are the following occurrences of the substrings:BACFAB.

In the third sample test there is no substring "AB" nor substring "BA".

给出一行字符，判断是否出现两个不重叠的字串“AB”和“BA”

思路：

暴力解就是了，看到标签是DP想了半天。最后发现直接用C++的find函数即可

#include<bits/stdc++.h>
using namespace std;
int main(){
	string s;
	cin >> s;
	int a = s.find("AB");
	int b = s.find("BA");
	if (a != -1 && s.find("BA", a + 2) != -1 || b != -1 && s.find("AB", b + 2) != -1)
		cout << "YES";
	else
		cout << "NO";
}