#include"iostream"
#include"cstdio"
#include"cstring"
using namespace std;
const int maxn=10000+5;
int value[maxn];
int main(){
int n;
while(cin>>n){
    memset(value,0,sizeof(value));
    int v;
    for(int i=0;i<n;i++){
            cin>>v;
        value[v]++;
    }
    int num=0;
    int b;
    int sum=0;
    for(int i=0;i<maxn;i++){
            sum+=value[i];
        if(num<value[i])
           {
               num=value[i];
               b=i;
           }
    }
    if(num>sum-num)
        cout<<b<<endl;
    else
        cout<<"-1"<<endl;
}
}