#include <stdio.h>
#include <stdlib.h>

int v[1000000];
int e,nrm,i,n,nr,x;

int main()
{
    freopen("elmaj.in","r",stdin);
    freopen("elmaj.out","w",stdout);

    scanf("%d",&n);

    for(i=0;i<n;i++){
        scanf("%d",&v[i]);
        x=v[i];
        if(nr==0){
            e=x;
            nr++;
        }else{
            if(e==x){
                nr++;
            }else{
                nr--;
            }
        }
    }
    for(i=0;i<n;i++){
        if(e==v[i]){
            nr++;
        }
    }
    if(nr<n/2+1){
        printf("-1");
        return 0;
    }
    printf("%d",e);
    return 0;
}