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
//------------------------------------------
#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <queue>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <tuple>

using namespace std;

//conversion
//------------------------------------------
inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

//math
//-------------------------------------------
template<class T> inline T sqr(T x) {return x*x;}

//typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;

//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define MT make_tuple
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())

//repetition
//------------------------------------------
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

//constant
//--------------------------------------------
const double EPS = 1e-10;
const double PI  = acos(-1.0);
const int DX[] = {0, 1, 0, -1};
const int DY[] = {-1, 0, 1, 0};

//other
//--------------------------------------------
#define RANGE(a, c, b) ((a <= b) && (b < c))

//clear memory
#define CLR(a) memset((a), 0 ,sizeof(a))

//debug
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

int solve(string snake){
	if(snake[0] == '>' &&
		snake[1] == '\''){
		int i = 2;
		while(snake[i] == '='){
			i++;
		}
		if(snake[i] != '#') return 0;
		int length = i - 2;
		i++;
		while(snake[i] == '='){
			i++;
		}
		int length2 = i -3 - length;
		if(length2 != length) return 0;
		if(snake[i] = '~' && 
			i == snake.length() - 1){
			return 1;
		}
	}else if(snake[0] == '>' &&
		snake[1] == '^'){
		int i = 2;
		while(snake[i] =='Q' &&
			snake[i + 1] == '='){
			i += 2;
		}
		if(snake[i] == '~' &&
			snake[i + 1] == '~' &&
			i + 1 == snake.length() - 1){
			return 2;
		}
	}
	return 0;
}

int main(int argc, char const *argv[])
{
	int n;
	cin >> n;
	REP(i, n){
		string snake;
		cin >> snake;
		string ans;
		switch(solve(snake)){
			case 0:
			ans = "NA";
			break;

			case 1:
			ans = "A";
			break;

			case 2:
			ans = "B";
			break;
		}
		cout << ans << endl;
	}
	
	return 0;
}

C++: #include<iostream>
#include<string>
using namespace std;

using namespace std;

int main(){
	int n;
	while(cin>>n,n){
		for(int x=0;x<n;++x){
			string line;
			cin>>line;
			string sol = "NA";
			int j = line.find('#');
			if(line.find('#')!=string::npos){
				bool flag = false;
				string a = "";
				string b = "";
				for(int x=2;x<line.size()-1;++x){
					if(line[x] == '#'){
						flag = true;
						continue;
					}
					if(!flag){
						a += line[x];
					}else{
						b += line[x];
					}
				}
				if(a==b)sol = "A";
//				cout<<a<<":"<<b<<endl;
			}else{
				bool flag = true;
				for(int x=2;x<line.size()-3;){
					if(line[x] !='Q' || line[x+1] != '=')flag = false;
//					cout<<line[x]<<":"<<line[x+1]<<endl;
					x++;
					x++;
				}
				if(flag)sol = "B";
			}
			cout<<sol<<endl;
		}
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
int main(){
  int i,n;
  string s;
  cin>>n;
  while(n--){
    cin>>s;
    if(s[0]=='>'&&s[1]=='\''&&s.size()%2==0){
      for(i=2;i<s.size();i++){
	if(i==s.size()/2&&s[i]!='#')break;
	if(i==s.size()/2){i++;continue;}
	if(i==s.size()-1&&s[i]=='~'){
	  cout<<"A"<<endl;
	  goto L;
	}
	if(s[i]!='='){cout<<i;break;}
      }
    }
    else if(s[0]=='>'&&s[1]=='^'&&s[3]=='Q'){
        for(i=2;i<s.size();i++){
	if(i==s.size()-2&&s[i]=='~'&&s[i+1]=='~'){
	  cout<<"B"<<endl;
	  goto L;
	}
	if(s[i]!='Q'||s[i+1]!='=')break;
	else i++;
      }
    }
    cout<<"NA"<<endl;
  L:;
  }
}

C++: 
#include<iostream>
#include<string>
using namespace std;

int main()
{
  int n,f,i,m;
  string s;
  cin>>n;
  while(n-->0){
    cin>>s;
    f=0;
    if(s[0]+s[1]=='>'+'\''){
      m=s.find('#');
      if(m!=string::npos){
	for(i=1;s[m-i]==s[m+i];)i++;
	if(i>1 && m-i==1 && m+i==s.size()-1 && s[m+i]=='~')f=1;
      }
    }else if(s[0]+s[1]=='>'+'^'){
      for(i=2;s[i]=='Q'&&s[i+1]=='=';)i+=2;
      if(i>2 && i==s.size()-2 && s[i]=='~' && s[i+1]=='~')f=2;
    }
    if(f)puts(f==1?"A":"B");
    else puts("NA");
  }
}

C++: #include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>

using namespace std;
typedef long long LL;
typedef pair<int, int> PII;
typedef complex<double> P;
static const double EPS = 1e-8;

#define FOR(i,k,n) for (int i=(k); i<(int)(n); ++i)
#define REP(i,n) FOR(i,0,n)

int main(void){
  int n;
  cin>>n;
  while(n--){
    string snake;
    cin>>snake;
    if(snake[0]=='>'&&snake[1]=='\''&&snake[snake.size()-1]=='~'){
      int count=0;
      int end;
      for(int i=2;i<snake.size()&&snake[i]=='='; i++){
        count++;
        end = i;
      }
      end++;
      if(count&&snake[end]=='#'&&end+count+2==snake.size()){
        bool yes = true;
        for(int i=end+1;i<snake.size()-1;i++){
          if(snake[i]!='=')yes = false;
        }
        if(yes){
          cout<<"A"<<endl;
        }else{
          cout<<"NA"<<endl;
        }
      }else{
        cout<<"NA"<<endl;
      }
    }else if(snake[0]=='>'&&snake[1]=='^'&&snake[snake.size()-1]=='~'&&snake[snake.size()-2]=='~'){
      bool yes = true;
      for(int i=2;i<snake.size()-2;i++){
        if(i%2==0&&snake[i]!='Q') yes = false;
        if(i%2==1&&snake[i]!='=') yes = false;
      }
      if(yes){
        cout<<"B"<<endl;
      }else{
        cout<<"NA"<<endl;
      }
    }
  }
  return 0;
}