Go: package main

import (
	"bufio"
	"os"
	"strconv"
	"strings"
	"fmt"
)

var scanner = bufio.NewScanner(os.Stdin)

func main() {
	scanner.Scan()
	n, _ := strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		ans := "NA"
		scanner.Scan()
		s := scanner.Text()
		if s[:2]==">'" && s[len(s)-1:] == "~" {
			tmp := s[2:len(s)-1]
			t := strings.Split(tmp, "#")
			if len(t) == 2 && len(t[0]) > 0 {
				valid := true
				for _, v := range t[0] {
					if string(v) != "=" {
						valid = false
						break
					}
				}
				if valid && t[0] == t[1] {
					ans = "A"
				}
			}
		} else if s[:2] == ">^" && s[len(s)-2:] == "~~" {
			t := s[2:len(s)-2]
			if len(t) > 0 && len(t)%2 == 0 {
				valid := true
				for i := 0; i < len(t); i += 2 {
					if t[i:i+2] != "Q=" {
						valid = false
						break
					}
				}
				if valid {
					ans = "B"
				}
			}
 		}
		fmt.Println(ans)
	}
}

C++: #include <iostream>
#include <iomanip>
#include <sstream>
#include <vector>
#include <string>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <stack>
#include <queue>
#include <deque>
#include <algorithm>
#include <functional>
#include <iterator>
#include <limits>
#include <numeric>
#include <utility>
#include <type_traits>
#include <cmath>
#include <cassert>
#include <cstdio>

using namespace std;
using namespace placeholders;

using LL = long long;
using ULL = unsigned long long;
using VI = vector< int >;
using VVI = vector< vector< int > >;
using VS = vector< string >;
using ISS = istringstream;
using OSS = ostringstream;
using PII = pair< int, int >;
using VPII = vector< pair< int, int > >;
template < typename T = int > using VT = vector< T >;
template < typename T = int > using VVT = vector< vector< T > >;
template < typename T = int > using LIM = numeric_limits< T >;

template < typename T > inline istream& operator>>( istream &s, vector< T > &v ){ for ( T &t : v ) { s >> t; } return s; }
template < typename T > inline ostream& operator<<( ostream &s, const vector< T > &v ){ for ( int i = 0; i < int( v.size() ); ++i ){ s << ( " " + !i ) << v[i]; } return s; }

template < typename T > struct getv_fmt;
template <> struct getv_fmt<       int >{ static constexpr const char *fmt = "%d"; };
template <> struct getv_fmt< long long >{ static constexpr const char *fmt = "%lld"; };
template < typename T > void getv( std::vector< T > &v ){ for_each( begin( v ), end( v ), []( T &a ){ scanf( getv_fmt< T >::fmt, &a ); } ); };

template < typename T > inline T fromString( const string &s ) { T res; istringstream iss( s ); iss >> res; return res; }
template < typename T > inline string toString( const T &a ) { ostringstream oss; oss << a; return oss.str(); }

#define NUMBERED( name, number ) NUMBERED2( name, number )
#define NUMBERED2( name, number ) name ## _ ## number
#define REP1( n ) REP2( NUMBERED( REP_COUNTER, __LINE__ ), n )
#define REP2( i, n ) REP3( i, 0, n )
#define REP3( i, m, n ) for ( int i = ( int )( m ); i < ( int )( n ); ++i )
#define GET_REP( a, b, c, F, ... ) F
#define REP( ... ) GET_REP( __VA_ARGS__, REP3, REP2, REP1 )( __VA_ARGS__ )
#define FOR( e, c ) for ( auto &&e : c )
#define ALL( c ) begin( c ), end( c )
#define AALL( a ) ( remove_all_extents< decltype( a ) >::type * )a, ( remove_all_extents< decltype( a ) >::type * )a + sizeof( a ) / sizeof( remove_all_extents< decltype( a ) >::type )
#define DRANGE( c, p ) begin( c ), begin( c ) + ( p ), end( c )

#define SZ( v ) ( (int)( v ).size() )
#define EXIST( c, e ) ( ( c ).find( e ) != ( c ).end() )

template < typename T > inline bool chmin( T &a, const T &b ){ if ( b < a ) { a = b; return true; } return false; }
template < typename T > inline bool chmax( T &a, const T &b ){ if ( a < b ) { a = b; return true; } return false; }

#define PB push_back
#define EM emplace
#define EB emplace_back
#define BI back_inserter

#define MP make_pair
#define fst first
#define snd second

#define DUMP( x ) cerr << #x << " = " << ( x ) << endl

bool is_a( const string &S )
{
	const int Ls = SZ( S );

	if ( S.find( ">'" ) != 0 || S.find( "~" ) != Ls - 1 )
	{
		return false;
	}

	string T = S.substr( 2, Ls - 3 );
	const int Lt = SZ( T );
	if ( Lt % 2 == 0 || T[ Lt / 2 ] != '#' )
	{
		return false;
	}
	T[ Lt / 2 ] = '=';

	return all_of( ALL( T ), bind( equal_to< char >(), _1, '=' ) );
}

bool is_b( const string &S )
{
	const int Ls = SZ( S );

	if ( S.find( ">^" ) != 0 || S.find( "~~" ) != Ls - 2 )
	{
		return false;
	}
	
	const string T = S.substr( 2, Ls - 4 );
	const int Lt = SZ( T );

	if ( Lt == 0 || Lt % 2 )
	{
		return false;
	}

	for ( int i = 0; i < Lt; i += 2 )
	{
		if ( T[i] != 'Q' || T[ i + 1 ] != '=' )
		{
			return false;
		}
	}
	return true;
}

int main()
{
	cin.tie( 0 );
	ios::sync_with_stdio( false );
	cout << setprecision( 12 ) << fixed;

	int N;
	cin >> N;

	REP( N )
	{
		string S;
		cin >> S;

		string res = "NA";
		if ( is_a( S ) )
		{
			res = "A";
		}
		if ( is_b( S ) )
		{
			res = "B";
		}
		cout << res << endl;
	}

	return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<string>
#include<queue>
#include<unordered_map>
#include<map>
using namespace std;

int main()
{
	int a;
	cin >> a;
	for (int b = 0; b < a; b++) {
		string s = "NA";
		string c;
		cin >> c;
		if (c[0]=='>'&&c[c.length()-1]=='~') {
			if (c[1] == '\''&&(c.length() & 1)==0) {
				bool A = true;
				for (int i = 3; i < c.length() - 2; i++) {
					if (i == c.length()/2) {
						if (c[i] != '#')A = false;
					}
					else {
						if (c[i] != '=')A = false;
					}
				}
				if (A)s = "A";
			}
			else if (c[1] == '^'&&c[c.length() - 2] == '~') {
				bool B = true;
				for (int d = 2; d < c.length() - 2; d += 2) {
					if (c[d] != 'Q' || c[d + 1] != '=')B = true;
				}
				if (B)s = "B";
			}
		}
		cout << s << endl;
	}
}