#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pll pair<int, int>
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define endl '\n'
#define ld long double
signed main(){
int n;cin>>n;
vector<array<int,2>> a(2*n);
for(int i=0;i<2*n;i++)cin>>a[i][0];
for(int i=0;i<2*n;i++)cin>>a[i][1];
vector<array<pair<int,int>,2>> r(2*n);
for(int i=0;i<2*n;i++){
r[i][1]=r[i][0]={(int)1e15, -1};
}
r[0][0]={1, 1};
r[0][1]={0, 0};
for(int i=1;i<2*n;i++){
for(int j=0;j<2;j++){
for(int k=0;k<2;k++){
if(a[i-1][k]<=a[i][j]) r[i][j].f=min(r[i-1][k].f, r[i][j].f),
r[i][j].s=max(r[i-1][k].s,r[i][j].s);
}
if(j==0 and r[i][j].s != -1)r[i][j].f++,r[i][j].s++;
//~ printf("x %lld y %lld, l %lld r %lld\n", i,j,r[i][j].f,r[i][j].s);
}
}
vector<int> ans(2*n,-1);
auto dfs=[&](auto& dfs, int x, int y, int t)->void{
//~ printf("dfs x %lld, y %lld, t %lld\n",x,y,t);
//~ fflush(stdout);
assert(r[x][y].f <= t and r[x][y].s >= t);
ans[x]=y;
if(y==0)t--;
if(x==0)return;
for(int j=0;j<2;j++){
if(a[x-1][j]<=a[x][y] and r[x-1][j].f <= t and t<=r[x-1][j].s){
dfs(dfs, x-1, j, t);
break;
}
}
};
if(r[2*n-1][0].f <= n and n <= r[2*n-1][0].s){
dfs(dfs, 2*n-1, 0, n);
}
else if (r[2*n-1][1].f <= n and n <= r[2*n-1][1].s){
dfs(dfs, 2*n-1, 1, n);
}
else {
cout<<-1;
return 0;
}
for(int i=0;i<2*n;i++){
assert(ans[i]!=-1);
if(ans[i]==0)cout<<'A';
else cout<<'B';
}
}
