#include <bits/stdc++.h>
using namespace std;
#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define F0R(i, b) for(int i = 0; i < (b); i++)
#define R0F(i, b) for(int i = (b) - 1; i >= 0; i--)
#define ROF(i, a, b) for(int i = (b) - 1; i >= (a); i--)
using pi = pair<int, int>;
int main() {
ios::sync_with_stdio(false), cin.tie(nullptr);
int N; cin >> N;
vector<int> A(2 * N), B(2 * N);
F0R(i, 2 * N) cin >> A[i];
F0R(i, 2 * N) cin >> B[i];
vector<array<pi, 2>> dp(2 * N, {{{1e9, -1e9}, {1e9, -1e9}}});
dp[0][0] = {1, 1};
dp[0][1] = {-1, -1};
FOR(i, 1, 2 * N) {
if(A[i - 1] <= A[i]) {
dp[i][0].second = max(dp[i][0].second, dp[i - 1][0].second + 1);
dp[i][0].first = min(dp[i][0].first, dp[i - 1][0].first + 1);
}
if(A[i - 1] <= B[i]) {
dp[i][1].second = max(dp[i][1].second, dp[i - 1][0].second - 1);
dp[i][1].first = min(dp[i][1].first, dp[i - 1][0].first - 1);
}
if(B[i - 1] <= A[i]) {
dp[i][0].second = max(dp[i][0].second, dp[i - 1][1].second + 1);
dp[i][0].first = min(dp[i][0].first, dp[i - 1][1].first + 1);
}
if(B[i - 1] <= B[i]) {
dp[i][1].second = max(dp[i][1].second, dp[i - 1][1].second - 1);
dp[i][1].first = min(dp[i][1].first, dp[i - 1][1].first - 1);
}
}
vector<int> choice(2 * N);
int sum = 0;
int lv = 1e9;
ROF(i, 0, 2 * N) {
if(lv >= A[i] && dp[i][0].second >= -sum && -sum >= dp[i][0].first) {
choice[i] = 0;
lv = A[i];
sum++;
} else if(lv >= B[i] && dp[i][1].second >= -sum && -sum >= dp[i][1].first) {
choice[i] = 1;
lv = B[i];
sum--;
} else {
cout << -1 << endl;
return 0;
}
}
F0R(i, 2 * N) {
if(choice[i] == 0) cout << 'A';
else cout << 'B';
}
}
