#include <bits/stdc++.h>
using namespace std ;
const int MAX = 1e6 + 10 ;
int a[MAX] , b[MAX] ;
int n ;
int take_min[MAX] , take_max[MAX] , take_free[MAX] ;
int taken[MAX] ;
int main()
{
ios_base::sync_with_stdio(0) ;
cin.tie(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] ;
for(int i = 0 ; i < 2*n-1 ; ++i)
{
if(min(a[i] , b[i]) > max(a[i+1] , b[i+1]))
return cout<<-1<<"\n" , 0 ;
if(min(a[i] , b[i]) > min(a[i+1] , b[i+1]))
take_max[i+1] = 1 ;
else if(take_max[i] && max(a[i] , b[i]) > min(a[i+1] , b[i+1]))
take_max[i+1] = 1 ;
}
for(int i = 2*n-1 ; i > 0 ; --i)
{
if(max(a[i] , b[i]) < max(a[i-1] , b[i-1]))
take_min[i-1] = 1 ;
else if(take_min[i] && min(a[i] , b[i]) < max(a[i-1] , b[i-1]))
take_min[i-1] = 1 ;
}
for(int i = 0 ; i < 2*n ; ++i)
{
if(take_max[i] && take_min[i])
return cout<<-1<<"\n" , 0 ;
if(take_max[i] || take_min[i])
continue ;
take_free[i] = 1 ;
if(i-1 >= 0 && (min(a[i] , b[i]) < max(a[i-1] , b[i-1]) && !take_min[i-1]))
take_free[i] = 0 ;
if(i+1 < 2*n && (max(a[i] , b[i]) > min(a[i+1] , b[i+1]) && !take_max[i+1]))
take_free[i] = 0 ;
}
vector< vector< pair<int , int> > >vp ;
bool flag = false ;
int ans = 0 , cnt = 0 ;
for(int i = 0 ; i < 2*n ; ++i)
{
flag &= (!take_free[i] && !take_max[i] && !take_min[i]) ;
if(take_max[i])
{
if(a[i] > b[i])
ans++ , taken[i] = 0 ;
else
ans-- , taken[i] = 1 ;
}
else if(take_min[i])
{
if(a[i] < b[i])
ans++ , taken[i] = 0 ;
else
ans-- , taken[i] = 1 ;
}
else if(take_free[i])
cnt++ ;
else
{
if(!flag)
vp.push_back({}) ;
else
{
if(min(a[i] , b[i]) >= max(a[i-1] , b[i-1]))
vp.push_back({}) ;
}
if(a[i] > b[i])
ans++ , taken[i] = 0 , vp.back().emplace_back(-2 , i) ;
else
ans-- , taken[i] = 1 , vp.back().emplace_back(2 , i) ;
flag = true ;
}
}
for(auto &v2 : vp)
{
int Max = 0 , Min = 0 , sum = 0 ;
for(auto &p : v2)
{
sum += p.first ;
Max = max(Max , sum) , Min = min(Min , sum) ;
}
if(ans > 0)
{
int a = min(-1 * Min , ans) ;
if((a & 1))
a -= (a & 1) ;
ans -= a ;
sum = 0 ;
for(auto &p : v2)
{
if(-1 * sum == a)
break ;
taken[p.second] ^= 1 ;
sum += p.first ;
}
}
else
{
int a = min(Max , -1 * ans) ;
if((a & 1))
a -= (a & 1) ;
ans += a ;
sum = 0 ;
for(auto &p : v2)
{
if(sum == a)
break ;
taken[p.second] ^= 1 ;
sum += p.first ;
}
}
}
for(int i = 0 ; i < 2*n ; ++i)
{
if(take_free[i])
{
if(ans < 0)
taken[i] = 0 , ans++ ;
else
taken[i] = 1 , ans-- ;
}
}
if(ans != 0)
return cout<<-1<<"\n" , 0 ;
for(int i = 0 ; i < 2*n ; ++i)
cout<<(char)('A' + taken[i]) ;
cout<<"\n" ;
return 0 ;
}
