#include<map>
#include<set>
#include<stack>
#include<queue>
#include<cmath>
#include<vector>
#include<cstdio>
#include<string>
#include<cstring>
#include<cstdlib>
#include<iostream>
#include<algorithm>
#define inf 0x0f0f0f0f
#define LL long long
#define eps 1e-8
using namespace std;

const int maxn = 10000+10;
int a[maxn];
int main()
{
    int n,x;
    while(scanf("%d",&n)!=EOF)
    {
        memset(a,0,sizeof a);
        for (int i=1;i<=n;i++)
        {
            scanf("%d",&x); a[x]++;
        }
        bool flag=0;
        for (int i=0;i<10000;i++)
        {
            if (a[i]>n-a[i]) {printf("%d\n",i);flag=1; break;}
        }
        if (!flag) printf("-1\n");
    }
    return 0;
}