#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  cin >> N;
  string S;
  cin >> S;
  bool ok = true;
  int cnt = 0;
  for (int i = 0; i < N; i++){
    if (S[i] == 'Q'){
      cnt++;
    }
    if (S[i] != '+' && S[i] != 'Q'){
      assert(false);
      ok = false;
    }
  }
  if (!ok){
    cout << -1 << endl;
  } else if (cnt == 0){
    cout << -1 << endl;
  } else {
    int s = -1;
    for (int i = 1; i * i <= N; i++){
      if (i * i == cnt){
        s = i;
      }
    }
    if (s == -1){
      cout << -1 << endl;
    } else if (N % s != 0){
      cout << -1 << endl;
    } else {
      assert(false);
      string ans = S.substr(0, N / s);
      for (int i = 0; i < N; i += N / s){
        if (S.substr(i, N / s) != ans){
          ok = false;
        }
      }
      if (!ok){
        cout << -1 << endl;
      } else {
        cout << ans << endl;
      }
    }
  }
}