#include<bits/stdc++.h>
using namespace std;
int N, A[1000010], B[1000010], cntA, cntB;
int dpA[1000010][2], dpB[1000010][2];
bool chk[1000010], ret[1000010];
int main(){
scanf("%d", &N);
for(int i = 0;i < 2*N;i++){
scanf("%d", &A[i]);
}
for(int i = 0;i < 2*N;i++){
scanf("%d", &B[i]);
}
dpA[0][0] = dpB[0][1] = 1;
dpA[0][1] = dpB[0][0] = 0;
int prev = min(A[0], B[0]);
for(int i = 1;i < 2*N;i++){
if(A[i] >= A[i - 1]) dpA[i][0] = dpA[i - 1][0] + 1;
if(A[i] >= B[i - 1]) dpA[i][0] = max(dpA[i][0], dpA[i - 1][1] + 1);
if(B[i] >= A[i - 1]) dpA[i][1] = dpA[i - 1][0];
if(B[i] >= B[i - 1]) dpA[i][1] = max(dpA[i][1], dpA[i - 1][1]);
if(B[i] >= A[i - 1]) dpB[i][1] = dpB[i - 1][0] + 1;
if(B[i] >= B[i - 1]) dpB[i][1] = max(dpB[i][1], dpB[i - 1][1] + 1);
if(A[i] >= A[i - 1]) dpB[i][0] = dpB[i - 1][0];
if(A[i] >= B[i - 1]) dpB[i][0] = max(dpB[i][0], dpB[i - 1][1]);
if(A[i] <= B[i]){
if(A[i] >= prev) prev = A[i];
else if(B[i] >= prev) prev = B[i];
else{
printf("-1");
return 0;
}
}
else{
if(B[i] >= prev) prev = B[i];
else if(A[i] >= prev) prev = A[i];
else{
printf("-1");
return 0;
}
}
}
if(max(dpA[2*N-1][0], dpA[2*N-1][1]) < N || max(dpB[2*N-1][0], dpB[2*N-1][1]) < N){
printf("-1");
return 0;
}
prev = 0;
for(int i = 0;i < 2*N;i++){
if(A[i] <= B[i]){
if(A[i] >= prev) {
ret[i] = true;
chk[i] = false;
prev = A[i];
cntA++;
}
else if(B[i] >= prev) {
ret[i] = false;
chk[i] = true;
prev = B[i];
cntB++;
}
}
else{
if(B[i] >= prev) {
ret[i] = true;
chk[i] = true;
prev = B[i];
cntB++;
}
else if(A[i] >= prev) {
ret[i] = false;
chk[i] = false;
prev = A[i];
cntA++;
}
}
}
vector<int> v;
for(int i = 0;i < 2*N-1;i++){
if(!ret[i]) continue;
if(max(A[i], B[i]) <= min(A[i+1], B[i+1])) v.push_back(i);
else if(max(A[i], B[i]) <= max(A[i+1], B[i+1]) && !ret[i+1]) v.push_back(i);
}
if(ret[2*N-1]) v.push_back(2*N-1);
for(int i = 0;i < v.size();i++){
if(cntA == cntB) break;
if(cntA < cntB){
int cnt, maxcnt = 0, maxi = v[i] + 1;
if(chk[v[i]]) {maxcnt = cnt = 1; maxi = v[i];}
else cnt = -1;
if(cntA + cnt == cntB - cnt){
chk[v[i]] = false;
goto print;
}
for(int j = v[i] - 1;j >= 0;j--){
if(!ret[j]) break;
if(max(A[j], B[j]) <= min(A[j+1], B[j+1])) break;
if(max(A[j], B[j]) <= max(A[j+1], B[j+1])){
if(chk[j]) cnt++;
else cnt--;
if(cntA + cnt == cntB - cnt){
for(int k = v[i];k >= j;k--){
if(chk[k]) chk[k] = false;
else chk[k] = true;
}
goto print;
}
if(cnt > maxcnt){
maxcnt = cnt;
maxi = j;
}
}
else break;
}
for(int j = v[i];j >= maxi;j--){
if(chk[j]) chk[j] = false;
else chk[j] = true;
}
cntA += maxcnt, cntB -= maxcnt;
}
else{
int cnt, maxcnt = 0, maxi = v[i] + 1;
if(!chk[v[i]]) {maxcnt = cnt = 1; maxi = v[i];}
else cnt = -1;
if(cntB + cnt == cntA - cnt){
chk[v[i]] = true;
goto print;
}
for(int j = v[i] - 1;j >= 0;j--){
if(!ret[j]) break;
if(max(A[j], B[j]) <= min(A[j+1], B[j+1])) break;
if(max(A[j], B[j]) <= max(A[j+1], B[j+1])){
if(!chk[j]) cnt++;
else cnt--;
if(cntB + cnt == cntA - cnt){
for(int k = v[i];k >= j;k--){
if(chk[k]) chk[k] = false;
else chk[k] = true;
}
goto print;
}
if(cnt > maxcnt){
maxcnt = cnt;
maxi = j;
}
}
else break;
}
for(int j = v[i];j >= maxi;j--){
if(chk[j]) chk[j] = false;
else chk[j] = true;
}
cntB += maxcnt, cntA -= maxcnt;
}
}
print:;
for(int i = 0;i < 2*N;i++){
if(chk[i]) printf("B");
else printf("A");
}
return 0;
}
