// oooo
/*
har chi delet mikhad bebar ~
gitar o ba khodet nabar! ~
;Amoo_Hasan;
*/
#include<bits/stdc++.h>
//#pragma GCC optimize("O3,no-stack-protector,unroll-loops")
//#pragma GCC target("avx2,fma")
using namespace std;
typedef long long ll;
typedef long double ld;
#define Sz(x) int((x).size())
#define All(x) (x).begin(), (x).end()
#define wtf(x) cout<<#x <<" : " <<x <<endl
#define mak make_pair
//constexpr int PRI = 1000696969;
constexpr ll INF = 1e18, N = 1e6 + 10, MOD = 1e9 + 7;
int a[N], b[N];
int main() {
ios :: sync_with_stdio(0), cin.tie(0); cout.tie(0);
int n; cin >>n;
for(int i = 0; i < 2 * n; i++) cin >>a[i];
for(int i = 0; i < 2 * n; i++) cin >>b[i];
for(int mask = 0; mask < (1 << (2 * n)); mask++) {
if(__builtin_popcount(mask) != n) continue;
vector<int> vc;
for(int j = 0; j < 2 * n; j++) {
if((mask >> j) & 1) vc.push_back(a[j]);
else vc.push_back(b[j]);
}
bool ex = 0;
for(int i = 1; i < Sz(vc); i++) {
if(vc[i] < vc[i - 1]) {
ex = 1;
break;
}
}
if(ex) continue;
string s = "";
for(int j = 0; j < 2 * n; j++) {
if((mask >> j) & 1) s.push_back('A');
else s.push_back('B');
}
cout<<s;
return 0;
}
cout<<-1;
return 0;
}
