#include<bits/stdc++.h>
using namespace std;
int n,a[500001],b[500001];
bitset<500005> dp[2];
bitset<500005> h[2][2001];
void read()
{
cin>>n;
for(int i=1;i<=2*n;i++)
cin>>a[i];
for(int i=1;i<=2*n;i++)
cin>>b[i];
}
void solve()
{
dp[0][1]=dp[1][0]=1;
h[0][1]=dp[0];
h[1][1]=dp[1];
for(int i=2;i<=2*n;i++)
{
bitset<500005> dp0,dp1;
if(a[i-1]<=a[i]&&b[i-1]>a[i])
{
dp0=(dp[0]<<1);
}
else if(a[i-1]>a[i]&&b[i-1]<=a[i])
{
dp0=(dp[1]<<1);
}
else if(a[i-1]<=a[i]&&b[i-1]<=a[i])
{
dp0=(dp[0]<<1)|(dp[1]<<1);
}
else dp0=0;
if(a[i-1]<=b[i]&&b[i-1]>b[i])
{
dp1=(dp[0]);
}
else if(a[i-1]>b[i]&&b[i-1]<=b[i])
{
dp1=(dp[1]);
}
else if(a[i-1]<=b[i]&&b[i-1]<=b[i])
{
dp1=(dp[0])|(dp[1]);
}
else dp1=0;
dp[0]=dp0;
dp[1]=dp1;
h[0][i]=dp[0];
h[1][i]=dp[1];
}
if(dp[0][n]||dp[1][n])
{
vector<int> v;
int j=n,l=1e9;
for(int i=2*n;i>=1;i--)
{
//cout<<l<<" !"<<endl;
if(h[0][i][j]&&l>=a[i])
{
j--;
l=a[i];
v.push_back(0);
}
else l=b[i],v.push_back(1);
}
for(int i=v.size()-1;i>=0;i--)
if(v[i]==0)cout<<"A";
else cout<<"B";
cout<<endl;
}
else cout<<-1<<endl;
}
int main()
{
read();
solve();
return 0;
}
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