#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ld long double
#define show(x,y) cout << y << " " << #x << endl;
#define show2(x,y,i,j) cout << y << " " << #x << " " << j << " " << #i << endl;
#define show3(x,y,i,j,p,q) cout << y << " " << #x << " " << j << " " << #i << " " << q << " " << #p << endl;
#define show4(x,y) for(auto it:x) cout << it << " "; cout << #y << endl;
typedef pair<long long,long long>pii;
typedef pair<pii,pii>pi2;
void solve(){
int n;
cin >> n;
int arr[2*n];
int arr2[2*n];
for(int x=0;x<2*n;x++){
cin >> arr[x];
}
for(int x=0;x<2*n;x++){
cin >> arr2[x];
}
vector<char>ans;
int cur=0;
for(int x=0;x<2*n;x++){
if(arr[x]>=cur&&arr2[x]>=cur){
if(arr[x]<=arr2[x]){
cur=arr[x];
ans.push_back('A');
}
else{
cur=arr2[x];
ans.push_back('B');
}
}
else if(arr[x]>=cur){
cur=arr[x];
ans.push_back('A');
}
else if(arr2[x]>=cur){
cur=arr2[x];
ans.push_back('B');
}
else{
cout << -1;
return;
}
}
for(auto it:ans)cout << it;
}
int32_t main(){
ios::sync_with_stdio(0);
cin.tie(0);
int t=1;
//cin >> t;
while(t--){
solve();
}
}
/*
4 5
0 1
0 2
1 2
1 3
2 3
*/
