#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define repr(i,n) for(int i = (int)(n); i >= 0; i--)
#define all(v) v.begin(),v.end()
typedef long long ll;

int vector_finder(vector<int> vec, int number){
    int len = vec.size();
    int cnt = 0;
    rep(i,len){
        if (vec[i] == number) cnt++;
    }
    if (cnt >= 1) return 1;
    else return 0;
}

int main(){
    int N;
    cin >> N;
    vector<int> vec(N);
    rep(i,N){
        cin >> vec[i];
    }
    vector<vector<int> > chouon(12, vector<int>(7));
    chouon[0][0] = 0;
    chouon[0][1] = 2;
    chouon[0][2] = 4;
    chouon[0][3] = 5;
    chouon[0][4] = 7;
    chouon[0][5] = 9;
    chouon[0][6] = 11;
    for (int i = 1; i <= 11; i++){
        for (int j = 0; j <= 6; j++){
            chouon[i][j] = (chouon[0][j] + i) % 12;
        }
    }
    bool possible = true;
    vector<bool> exist(12, true);
    if (N >= 8){
        possible = false;
    }
    else{
        rep(i,12){
            rep(j,N){
                if (vector_finder(chouon[i], vec[j]) == 0){
                    exist[i] = false;
                }
            }
        }
    }
    int count = 0;
    rep(i,12){
        if (exist[i]) count += (10000 + i);
    }
    if (count == 0 || count >= 20000) cout << -1 << endl;
    else cout << (count % 10000) << endl;
}