// Om Namah Shivaya
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x, y) ((x + y - 1) / (y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
#define rep(i, n) for(int i = 0; i < n; ++i)
#define rep1(i, n) for(int i = 1; i <= n; ++i)
#define rev(i, s, e) for(int i = s; i >= e; --i)
#define trav(i, a) for(auto &i : a)
template<typename T>
void amin(T &a, T b) {
a = min(a, b);
}
template<typename T>
void amax(T &a, T b) {
a = max(a, b);
}
#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif
/*
refs:
https://codeforces.com/blog/entry/74871?#comment-590839
proof for lemma and a nicer way to think about the problem => https://codeforces.com/blog/entry/74871?#comment-590887
*/
const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
void solve(int test_case)
{
ll n; cin >> n;
vector<ll> a(2*n+5), b(2*n+5);
rep1(i,2*n) cin >> a[i];
rep1(i,2*n) cin >> b[i];
pll dp[2*n+5][2];
rep(i,2*n+5) rep(j,2) dp[i][j] = {inf2,-inf2};
dp[0][0] = {0,0};
rep1(i,2*n){
rep(x,2){
rep(y,2){
ll v1 = a[i], v2 = a[i-1];
if(x) v1 = b[i];
if(y) v2 = b[i-1];
if(v1 >= v2){
amin(dp[i][x].ff,dp[i-1][y].ff+(x^1));
amax(dp[i][x].ss,dp[i-1][y].ss+(x^1));
}
}
}
}
ll x = -1;
rep(j,2){
if(dp[2*n][j].ff <= n and dp[2*n][j].ss >= n){
x = j;
}
}
if(x == -1){
cout << -1 << endl;
return;
}
string ans = "";
ll want = n;
rev(i,2*n,1){
if(!x) ans.pb('A'), want--;
else ans.pb('B');
bool ok = false;
rep(y,2){
ll v1 = a[i], v2 = a[i-1];
if(x) v1 = b[i];
if(y) v2 = b[i-1];
if(v1 >= v2){
if(dp[i-1][y].ff <= want and dp[i-1][y].ss >= want){
x = y;
ok = true;
break;
}
}
}
assert(ok);
}
assert(want == 0);
reverse(all(ans));
cout << ans << endl;
}
int main()
{
fastio;
int t = 1;
// cin >> t;
rep1(i, t) {
solve(i);
}
return 0;
}
