#include<iostream>
using namespace std;
int N;
string S;
int main()
{
	cin>>N>>S;
	if(!(1<=N&&N<=100000))
	{
		cerr<<"N range error"<<endl;
		return 1;
	}
	if(N!=S.size())
	{
		cout<<"N not equal to |S|"<<endl;
		return 1;
	}
	for(char c:S)
	{
		if(!('a'<=c&&c<='z'||'A'<=c&&c<='Z'))
		{
			cout<<"S contains non-alphabetic character"<<endl;
			return 1;
		}
	}
	for(int c=1;c<=N;c++)if(N%c==0)
	{
		string T=S.substr(0,N/c);
		bool ok=true;
		int Qc=0;
		for(char t:T)
		{
			if(t=='Q')Qc++;
			if(t=='H')ok=false;
		}
		if(Qc!=c)ok=false;
		for(int i=0;i<c;i++)if(T!=S.substr(i*(N/c),N/c))ok=false;
		if(ok)
		{
			cout<<T<<endl;
			return 0;
		}
	}
	cout<<-1<<endl;
	return 0;
}