#include "bits/stdc++.h"
using namespace std;
const int N=1e6;
int n;
int a[N], b[N];
int dp[N][2][2];
int main(){
cin.tie(0)->sync_with_stdio(0);
cin >> n;
for(int i=0; i<2*n; i++){
cin >> a[i];
}
for(int i=0; i<2*n; i++){
cin >> b[i];
}
// dp[i][A/B][min/max]
dp[0][0][0]=dp[0][0][1]=1;
dp[0][1][0]=dp[0][1][1]=0;
for(int i=1; i<2*n; i++){
dp[i][0][0]=dp[i][1][0]=1e9;
dp[i][0][1]=dp[i][1][1]=-1e9;
dp[i][0][0]=min(a[i-1]<=a[i]?dp[i-1][0][0]+1:1e9, b[i-1]<=a[i]?dp[i-1][1][0]+1:1e9);
dp[i][0][1]=max(a[i-1]<=a[i]?dp[i-1][0][1]+1:-1e9, b[i-1]<=a[i]?dp[i-1][1][1]+1:-1e9);
dp[i][1][0]=min(a[i-1]<=b[i]?dp[i-1][0][0]:1e9, b[i-1]<=b[i]?dp[i-1][1][0]:1e9);
dp[i][1][1]=max(a[i-1]<=b[i]?dp[i-1][0][1]:-1e9, b[i-1]<=b[i]?dp[i-1][1][1]:-1e9);
// cout << dp[i][0][0] << " " << dp[i][0][1] << " " << dp[i][1][0] << " " << dp[i][1][1] << "\n";
}
if((dp[2*n-1][0][0]<=n && dp[2*n-1][0][1]>=n) || (dp[2*n-1][1][0]<=n && dp[2*n-1][1][1]>=n)){
int k=n;
string ans(" ", 2*n);
// cout << ans.size() << "\n";
int lst=1e9;
for(int i=2*n-1; i>=1; i--){
// cout << "k " << k << " lst " << lst << "\n";
if(a[i]<=lst && dp[i][0][0]<=k && dp[i][0][1]>=k){
ans[i]='A';
lst=a[i];
k--;
}
else ans[i]='B', lst=b[i];
}
if(k) ans[0]='A';
else ans[0]='B';
cout << ans;
}
else cout << -1;
}
