/***Farhan132***/
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma")
//#pragma GCC optimization ("unroll-loops")
//#pragma GCC optimize("Ofast,fast-math")
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef double dd;
typedef vector<ll> vll;
typedef pair<ll , ll> ii;
typedef vector< ii > vii;
typedef pair < pair < ll , ll > , pair < ll , ll > > cm;
typedef tuple < ll, ll, ll > tp;
#define ff first
#define ss second
#define pb push_back
#define in insert
#define f0(b) for(int i=0;i<(b);i++)
#define f00(b) for(int j=0;j<(b);j++)
#define f1(b) for(int i=1;i<=(b);i++)
#define f11(b) for(int j=1;j<=(b);j++)
#define f2(a,b) for(int i=(a);i<=(b);i++)
#define f22(a,b) for(int j=(a);j<=(b);j++)
#define sf(a) scanf("%lld",&a)
#define sff(a,b) scanf("%lld %lld", &a , &b)
#define pf(a) printf("%lld\n",a)
#define pff(a,b) printf("%lld %lld\n", a , b)
#define bug printf("**!\n")
#define mem(a , b) memset(a, b ,sizeof(a))
#define front_zero(n) __builtin_clzll(n)
#define back_zero(n) __builtin_ctzll(n)
#define total_one(n) __builtin_popcount(n)
#define clean fflush(stdout)
//const ll mod = (ll) 998244353;
const ll mod = (ll) 1e9 + 7;
const ll maxn = (ll)1e8 + 5;
const int nnn = 1048590;
const int inf = numeric_limits<int>::max()-1;
//const ll INF = numeric_limits<ll>::max()-1;
const ll INF = (ll)1e18;
ll dx[]={0,1,0,-1};
ll dy[]={1,0,-1,0};
ll dxx[]={0,1,0,-1,1,1,-1,-1};
ll dyy[]={1,0,-1,0,1,-1,1,-1};
bool USACO = 0;
mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template <typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const ll N = 1e6 + 5;
ll dp_mx[N][2] , dp_mn[N][2];
ll a[N] , b[N];
void solve(){
ll n; cin >> n;
for(ll i = 1; i <= 2*n; i++) cin >> a[i];
for(ll i = 1; i <= 2*n; i++) cin >> b[i];
for(ll i = 2; i <= 2*n; i++){
if(min(a[i - 1], b[i - 1]) > max(a[i], b[i])){
cout << "-1\n"; return;
}
}
mem(dp_mn, 0);
mem(dp_mx, 0);
b[2*n + 1] = a[2*n + 1] = INF;
for(ll i = 2*n; i >= 1; i--){
dp_mn[i][0] = dp_mn[i][1] = INF;
dp_mx[i][0] = dp_mx[i][1] = -INF;
if(a[i] <= a[i + 1]){
dp_mn[i][0] = min(dp_mn[i][0], dp_mn[i + 1][0] + 1);
dp_mx[i][0] = max(dp_mx[i][0], dp_mx[i + 1][0] + 1);
}
if(a[i] <= b[i + 1]){
dp_mn[i][0] = min(dp_mn[i][0], dp_mn[i + 1][1] + 1);
dp_mx[i][0] = max(dp_mx[i][0], dp_mx[i + 1][1] + 1);
}
if(b[i] <= a[i + 1]){
dp_mn[i][1] = min(dp_mn[i][1], dp_mn[i + 1][0]);
dp_mx[i][1] = max(dp_mx[i][1], dp_mx[i + 1][0]);
}
if(b[i] <= b[i + 1]){
dp_mn[i][1] = min(dp_mn[i][1], dp_mn[i + 1][1]);
dp_mx[i][1] = max(dp_mx[i][1], dp_mx[i + 1][1]);
}
}
ll need = n;
if( !(min(dp_mn[1][0], dp_mn[1][1]) <= n && n <= max(dp_mx[1][0], dp_mx[1][1]) ) ){
cout << "-1\n"; return;
}
string s = ""; ll last = -1;
for(ll i = 1; i <= 2*n; i++){
if( (dp_mn[i][1] <= need && need <= dp_mx[i][1]) && last <= b[i]){
s += "B"; last = b[i];
}else{
s += "A"; need--; last = a[i];
}
}
cout << s;
return;
}
int main() {
#ifdef LOCAL
freopen("in", "r", stdin);
freopen("out", "w", stdout);
auto start_time = clock();
#else
ios_base::sync_with_stdio(0); cin.tie(NULL); cout.tie(NULL);
#endif
//pre(N);
ll T = 1, CT = 0; //cin >> T;
while(T--){
solve();
}
#ifdef LOCAL
auto end_time = clock();
cerr<< "Execution time: "<<(end_time - start_time)*(int)1e3/CLOCKS_PER_SEC<<" ms\n";
#endif
return 0;
}
