#include<stdio.h>

int main()
{
	unsigned long long v[1000000],i,a=0,n,e=0;
	freopen("elmaj.in","r",stdin);
	freopen("elmaj.out","w",stdout);
	scanf("%ld",&n);
	for(i=0;i<n;i++)
	{
		scanf("%ld",&v[i]);
		if(!a) e=v[i];
		else
		if(v[i]!=e) a--;
		else a++;
	}
	if(!a) printf("-%d",1);
	else 
	{
		a=0;
		for(i=0;i<n;i++)
		if(e==v[i]) a++;
		if(a>=n/2+1) printf("%ld%ld",e,a);
		else printf("-%d",1);
	}
	return 0;
}