#include <fstream>
#include <algorithm>
using namespace std;
long long v[1000001];

int main()
{
    ifstream f("elmaj.in");
    ofstream g("elmaj.out");
    int i, numar, fr=1, verif=0;
    long long n;
    f>>n;
    for(i=1;i<=n;++i)
        f>>v[i];
    for(i=2;i<=n;++i)
    {   if (v[i]==v[i-1]) fr++;
         else fr--;
        if (fr==0) { numar=v[i]; fr=1; }
    }
    for (i=1;i<=n;++i)
    {   if (v[i]==numar) verif++;
    }
    if (verif>n/2) g<<numar;
        else g<<"-1";
    return 0;
}