#include <fstream>
#include <iostream>
#include <ctime>
#include <cstdlib>
#define nmax 1000005

using namespace std;

ifstream fin("elmaj.in");
ofstream fout("elmaj.out");

int n, k;
int A[nmax];

void read() {
    fin >> n;
    for (int i = 1; i <= n; i++)
        fin >> A[i];
    k = (n>>1);
}

int q(int st, int dr) {
    int i = st;
    int j = dr;
    int pivot = A[i+rand()%(j-i+1)];
    while (1) {
        for (; A[i] < pivot;) i++;
        for (; A[j] > pivot;) j--;
        if (i <= j)
            swap(A[i++], A[j--]);
        else
            return j;
    }
    return 0;
}

void solve(int st, int dr, int k) {
    if (st == dr)
        return;
    int hi = q(st, dr);
    int len = hi - st + 1;
    if (k <= len)
        solve(st, hi, k);
    else
        solve(hi+1, dr, k-len);
}

int main() {
    
    srand(time(NULL));
    
    read();
    solve(1, n, k);
    
    int nr = 0;
    for (int i = 1; i <= n; i++)
        if (A[i] == A[k])
            nr++;
    
    nr > (n>>1) ? fout << A[k] : fout << -1;
    
    fin.close();
    fout.close();
    
    return 0;
}