#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <cmath>
using namespace std;
int a[10002];
int main ()
{
    int n,i;
    while (scanf("%d",&n) == 1)
    {
        memset(a,0,sizeof(a));
        int temp;
        for (i = 0; i < n; i++)
        {
            scanf("%d",&temp);
            a[temp]++;
        }
        int ans = -1;
        for (i = 0; i <= 9999; i++)
        {
            if (a[i] > (n / 2))
            {
                ans = i;
                break;
            }
        }
        printf("%d\n",ans);
    }
    return 0;
}