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 <vector>
#include <list>
#include <map>
#include <set>
#include <unordered_set>
#include <unordered_map>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <queue>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <fstream>
#include <cstdio>
#include <climits>
#include <complex>
#include <cstdint>
#include <tuple>

#define M_PI       3.14159265358979323846

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(); }
inline int readInt() { int x; scanf("%d", &x); return x; }

//typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<int, PII> TIII;
typedef long long LL;
typedef unsigned long long ULL;
typedef vector<LL> VLL;
typedef vector<VLL> VVLL;

//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 SZ(a) int((a).size())
#define SQ(a) ((a)*(a))
#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,s,n) for(int i=s;i<(int)n;++i)
#define REP(i,n) FOR(i,0,n)
#define MOD 1000000007

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define trav(a, x) for(auto& a : x)
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()


struct Edge {
    int to, cost, nm;
    Edge(int to, int cost, int nm): to(to), cost(cost), nm(nm) {}
};

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vector<Edge>> AdjList;
AdjList graph;
#define chmin(x,y) x=min(x,y)
#define chmax(x,y) x=max(x,y)
const int INF = 100000000;

ll GCD(ll a, ll b){
    if(a < b) swap(a, b);
    if(b == 0) return a;
    return GCD(b, a%b);
}

bool cmp(const pii& a, const pii& b){
    if(a.first == b.first){
        return a.second < b.second;
    }
    return a.first < b.first;
}

int main() {

    //cout << fixed << setprecision(2);

    int n;
    cin >> n;
    for(int i=0; i<n; ++i){
        string s; cin >> s;
        int n = s.size();

        if(n>2 && s[0] == '>' && s[1] =='\''){

            if(s[n-1] != '~'){
                cout << "NA" << endl;
            }else{
                int l = 2, r = n-2;
                bool ok = true;
                int stmt = 0;
                int cnt1=0, cnt2=0;
                for(int j=l; j<=r; ++j){
                    if(s[j] == '#') stmt++;
                    else if(s[j]=='='){
                        if(stmt == 0) cnt1++;
                        else if(stmt == 1) cnt2++;
                        else ok = false;
                    }else ok = false;
                }
                if(ok){
                    if(cnt1 >= 1 && (cnt1 == cnt2)){
                        cout << "A" << endl;
                    }else{
                        cout << "NA" << endl;
                    }
                }else{
                    cout << "NA" << endl;
                }
            }
        }else if(n > 2 && s[0] == '>' && s[1] == '^'){
            if(s[n-2] == '~' && s[n-1] == '~'){
                if(n%2 == 1){
                    cout << "NA" << endl;
                }else {
                    bool ok = true;
                    int cnt = 0;
                    for (int j = 2; j <= n - 3; j+=2) {
                        if(s[j] == 'Q' && s[j+1] == '='){
                            cnt++;
                        }else{
                            ok = false;
                        }
                    }
                    if(cnt>=1 && ok){
                        cout << "B" << endl;
                    }else{
                        cout << "NA" << endl;
                    }
                }
            }else{
                cout << "NA" << endl;
            }
        }else{
            cout << "NA" << endl;
        }
    }
    return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
int main()
{
	bool b;
	int n, i, j, t, c[2];
	char s[201];
	cin >> n;
	for (i = 0; i < n; i++)
	{
		b = true;
		cin >> s;
		if (s[0] == '>')
		{
			if (s[1] == '\'')
			{
				for (j = 2, t = c[0] = c[1] = 0; j < strlen(s)-1; j++)
				{
					if (s[j] == '=')
						c[t]++;
					else if (t == 0 && s[j] == '#')
						t++;
					else
					{
						b = false;
						break;
					}
				}
				if (b && c[0] == c[1] && s[strlen(s)-1] == '~')
					cout << "A" << endl;
				else
					cout << "NA" << endl;
				continue;
			}
			else if (s[1] == '^')
			{
				for (j = 2; j < strlen(s)-2; j+=2)
				{
					if (s[j] != 'Q' || s[j+1] != '=')
					{
						b = false;
						break;
					}
				}
				if (b && s[strlen(s)-2] == '~' && s[strlen(s)-1] == '~')
					cout << "B" << endl;
				else
					b = false;
				continue;
			}
			else
				b = false;
		}
		else
			b = false;
		if (!b)
			cout << "NA" << endl;
	}
}

C++: #include <bits/stdc++.h>
using namespace std;

int main() {
    int n; cin >> n;
    
    for (int i=0; i<n; i++) {
        string S; cin >> S;
        
        if (S.size()<4) {
            cout << "NA" << endl;
            continue;
        }
        
        if (S.substr(0, 2)==">'" && S[S.size()-1]=='~') {
            int mark = -1;
            for (int j=2; j<S.size()-1; j++) {
                if (S[j]=='#') mark = j;
            }
            bool flag = true;
            for (int j=2; j<S.size()-1; j++) {
                if (j==mark) continue;
                if (S[j]!='=') flag = false;
            }
            if (flag && mark!=-1 && mark-2==S.size()-2-mark && mark-2>0) cout << 'A' << endl;
            else cout << "NA" << endl;
        }
        else if (S[0]=='>' && S[1]=='^' && S[S.size()-2]=='~' && S[S.size()-1]=='~') {
            int idx = 2, cnt = 0;
            while (true) {
                if (S[idx]=='Q' && S[idx+1]=='=') {
                    cnt++;
                    idx += 2;
                }
                else break;
            }
            if (cnt>0 && idx==S.size()-2) cout << 'B' << endl;
            else cout << "NA" << endl;
        }
        else cout << "NA" << endl;
    }
}