#include <iostream>
#include <cstring>
#include <vector>
using namespace std;
const int MAXN = 1e6 + 5;
int n;
int a[MAXN][2];
namespace MaxA
{
int memo[MAXN][2];
int rec(int ind, int lastChoice)
{
if(ind==n) return 0;
int ans = -MAXN;
int lastVal = ((ind==0)?-1:a[ind-1][lastChoice]);
for(int c = 0;c<2;c++)
{
if(lastVal<=a[ind][c])
ans = max(ans, (c==0) + rec(ind+1, c));
}
return ans;
}
vector <int> solve()
{
memset(memo, -1, sizeof(memo));
vector <int> ans = {};
int aCnt = rec(0, 0), lastVal = -1;
for(int i = 0;i<n;i++)
{
for(int c = 0;c<2;c++)
{
if(lastVal<=a[i][c] && (c==0) + rec(i+1, c)==aCnt)
{
ans.push_back(c);
aCnt -= (c==0);
lastVal = a[i][c];
break;
}
}
}
return ans;
}
}
pair <int, int> maxB[MAXN];
int main()
{
ios::sync_with_stdio(false);
cin.tie(NULL);
cin >> n;n *= 2;
for(int i = 0;i<n;i++) cin >> a[i][0];
for(int i = 0;i<n;i++) cin >> a[i][1];
for(int i = 0;i<n-1;i++)
{
if(min(a[i][0], a[i][1])>max(a[i+1][0], a[i+1][1]))
{
cout << "-1" << '\n';
return 0;
}
}
int aCnt = 0;
vector <int> s = MaxA::solve();
for(int i = 0;i<n;i++) aCnt += (s[i]==0);
if(aCnt<n/2)
{
cout << "-1" << '\n';
return 0;
}
//for(int x: s) cout << x;
//cout << '\n';
for(int i = 0;i<n;i++)
{
maxB[i] = {0, 0};
if(i!=0) maxB[i] = max(maxB[i], make_pair(maxB[i-1].first, 0));
if(i==n-1 || a[i][1]<=a[i+1][s[i+1]])
{
for(int j = i;j>=0;j--)
{
if(s[j]==1) break;
if(j!=i && a[j][1]>a[j+1][1]) break;
if(j==0 || a[j-1][s[i-1]]<=a[j][1])
{
int val = ((j-2>=0)?maxB[j-2].first:0);
maxB[i] = max(maxB[i], make_pair(val+(i-j+1), (i-j+1)));
}
}
}
}
int ind = -1;
int toCompensate = aCnt - n/2;
for(int i = 0;i<n;i++)
{
if(maxB[i].first>=toCompensate)
{
ind = i;
break;
}
}
if(ind==-1)
{
cout << "-1" << '\n';
return 0;
}
while(toCompensate!=0)
{
if(maxB[ind].first<=toCompensate)
{
//cout << ind << '\n';
toCompensate -= maxB[ind].second;
for(int i = ind-maxB[ind].second+1;i<=ind;i++)
s[i] = 1;
ind = ind - maxB[ind].second - 1;
}
else
{
//TODO
break;
}
}
for(int x: s) cout << char('A'+x);
cout << '\n';
}
