#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef pair<ll,ll> P;
typedef vector<ll> VI;
typedef vector<VI> VVI;
#define REP(i,n) for(int i=0;i<(n);i++)
#define ALL(v) v.begin(),v.end()
constexpr ll MOD=1000000007;
constexpr ll INF=2e18;

int main(){
    int n; cin >> n;
    string s; cin >> s;
    int q=0;
    REP(i,n){
        if(s[i]=='Q'){
            q++;
        }
        else if(s[i]!='+'){
            cout << -1 << endl;
            return 0;
        }
    }
    int m=sqrt(q);
    if(m*m==q&&(n-q)%m==0){
        bool f=1;
        REP(i,m){
            for(int j=i;j<n;j+=n/m){
                if(s[i]!=s[j]){
                    cout << -1 << endl;
                    return 0;
                }
            }
        }
        REP(i,n/m) cout << s[i];
        cout << endl;
    }
    else{
        cout << -1 << endl;
    }
    return 0;
}