#include <bits/stdc++.h>
#define endl "\n"
#define ll long long
using namespace std;
const int mxN = 2001;
int dp[2*mxN][2][mxN+1];
vector<int> A(2*mxN),B(2*mxN);
int N;
string res(int i,int j,int k){
//cout << i << ' ' << j << ' ' << k << endl;
if(i == 0){
if(j == 0)
return "A";
else
return "B";
}
if(j == 0){
if(dp[i-1][0][k-1] && A[i-1] <= A[i]){
return res(i-1,0,k-1)+'A';
}
else if(dp[i-1][1][k-1] && B[i-1] <= A[i]){
return res(i-1,1,k-1)+'A';
}
}
else{
if(dp[i-1][0][k] && A[i-1] <= B[i]){
return res(i-1,0,k)+'B';
}
else if(dp[i-1][1][k] && B[i-1] <= B[i]){
return res(i-1,1,k)+'B';
}
}
return "";
}
void solve(){
cin >> N;
for(int i=0;i<2*N;i++){
cin >> A[i];
}
for(int i=0;i<2*N;i++)
cin >> B[i];
memset(dp,0,sizeof(dp));
dp[0][0][1] = 1;
dp[0][1][0] = 1;
for(int i=1;i<2*N;i++){
for(int j=0;j<=N;j++){
if(j && A[i-1] <= A[i])
dp[i][0][j] |= dp[i-1][0][j-1];
if(j && B[i-1] <= A[i])
dp[i][0][j] |= dp[i-1][1][j-1];
if(B[i-1] <= B[i])
dp[i][1][j] |= dp[i-1][1][j];
if(A[i-1] <= B[i])
dp[i][1][j] |= dp[i-1][0][j];
}
}
/*for(int cnt=0;cnt <= N;cnt++){
cout << "cnt : " << cnt << endl;
for(int j=0;j<2;j++){
for(int i=0;i<2*N;i++){
cout << dp[i][j][cnt] << ' ';
}
cout << endl;
}
cout << endl;
}*/
if(dp[2*N-1][0][N]){
//cout << res(2*N-2,0,N-1) << endl;
string ans = res(2*N-1,0,N);
//reverse(ans.begin(),ans.end());
cout << ans << endl;
}
else if(dp[2*N-1][1][N]){
//cout << 'B'+res(2*N-2,1,N) << endl;
string ans = res(2*N-1,1,N);
//reverse(ans.begin(),ans.end());
cout << ans << endl;
}
else{
cout << -1 << endl;
}
}
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
int t = 1;
//cin >> t;
while(t--){
solve();
}
return 0;
}
