#include <bits/stdc++.h>
#include <bits/extc++.h>
#define StarBurstStream ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define iter(a) a.begin(), a.end()
#define riter(a) a.rbegin(), a.rend()
#define lsort(a) sort(iter(a))
#define gsort(a) sort(riter(a))
#define pb(a) push_back(a)
#define eb(a) emplace_back(a)
#define pf(a) push_front(a)
#define ef(a) emplace_front(a)
#define pob pop_back()
#define pof pop_front()
#define mp(a, b) make_pair(a, b)
#define F first
#define S second
#define mt make_tuple
#define gt(t, i) get<i>(t)
#define tomax(a, b) ((a) = max((a), (b)))
#define tomin(a, b) ((a) = min((a), (b)))
#define topos(a) ((a) = (((a) % MOD + MOD) % MOD))
#define uni(a) a.resize(unique(iter(a)) - a.begin())
#define printv(a, b) {bool pvaspace=false; \
for(auto pva : a){ \
if(pvaspace) b << " "; pvaspace=true;\
b << pva;\
}\
b << "\n";}
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pdd = pair<ld, ld>;
using tiii = tuple<int, int, int>;
const ll MOD = 1000000007;
const ll MAX = 2147483647;
template<typename A, typename B>
ostream& operator<<(ostream& o, pair<A, B> p){
return o << '(' << p.F << ',' << p.S << ')';
}
ll ifloor(ll a, ll b){
if(b < 0) a *= -1, b *= -1;
if(a < 0) return (a - b + 1) / b;
else return a / b;
}
ll iceil(ll a, ll b){
if(b < 0) a *= -1, b *= -1;
if(a > 0) return (a + b - 1) / b;
else return a / b;
}
int main(){
StarBurstStream
int n;
cin >> n;
vector<vector<int>> a(2, vector<int>(2 * n + 1));
vector<int> c(2 * n + 1);
for(int i = 1; i <= 2 * n; i++) cin >> a[0][i];
for(int i = 1; i <= 2 * n; i++) cin >> a[1][i];
int lst = 0;
int t = 0;
for(int i = 1; i <= 2 * n; i++){
int mn = a[0][i] <= a[1][i] ? 0 : 1;
if(lst <= a[mn][i]) c[i] = mn;
else if(lst <= a[!mn][i]) c[i] = !mn;
else{
cout << "-1\n";
return 0;
}
lst = a[c[i]][i];
if(c[i] == 0) t++;
else t--;
}
// printv(c, cerr);
int rp = 2 * n, tmp = 0;
bool no = false;
for(int i = 2 * n; i >= 1 && t != 0; i--){
if(a[c[i]][i] > a[!c[i]][i]){
no = true;
continue;
}
if(i < 2 * n && a[!c[i]][i] <= a[c[i + 1]][i + 1]){
rp = i;
tmp = 0;
no = false;
}
else if(i < 2 * n && a[!c[i]][i] > a[!c[i + 1]][i + 1]){
no = true;
}
if(no) continue;
if(c[i] == 0) tmp -= 2;
else tmp += 2;
// cerr << "test " << i << " " << c[i] << " " << tmp << " " << t << " " << rp << "\n";
if((ll)tmp * t >= 0) continue;
t += tmp;
for(int j = i; j <= rp; j++) c[j] = !c[j];
rp = i - 1;
tmp = 0;
}
if(t != 0){
cout << "-1\n";
return 0;
}
for(int i = 1; i <= 2 * n; i++){
if(c[i] == 0) cout << "A";
else cout << "B";
}
cout << "\n";
return 0;
}
