#include<algorithm>
#include<fstream>
using namespace std;
int v[1000005],n;
int main()
{
    ifstream fin("elmaj.in");
    ofstream fout("elmaj.out");
    int i,j,s,x,a;
    fin>>n;
    s=1;
    for(i=1;i<=n;i++)
    fin>>v[i];
    sort(v+1,v+n+1);
    a=v[1];
    x=(n/2)+1;
    for(i=2;i<=n;i++)
    {
        if(a==v[i])s=s+1;
        else
        s=1;
        if(s>=x)
        fout<<v[i]<<" "<<s<<" ";
        a=v[i];
    }
    if(s==1)fout<<"-1";
    fin.close();
    fout.close();
}