Codeforces Round #306 (Div. 2) A. Two Substrings【字符串/判断所给的字符串中是否包含不重叠的“BA” “AB”两个字符串】

A. Two Substrings

time limit per test

2 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

You are given string s. Your task is to determine if the given string s 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 between 1 and 105 consisting of uppercase Latin letters.

Output

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

Examples

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".

【分析】：strstr函数判断AB和BA。

strstr(str1,str2) 函数用于判断字符串str2是否是str1的子串。如果是，则该函数返回str2在str1中首次出现的地址；否则，返回NULL。

【代码】：

#include<bits/stdc++.h>
using namespace std;
char str[200000],*p;
int main()
{
    cin>>str;
    if( (p=strstr(str,"AB")) && (strstr(p+2,"BA")) ) puts("YES");
    else if( (p=strstr(str,"BA")) && strstr(p+2,"AB") ) puts("YES");
    else puts("NO");
    return 0;
}