卡秒过
妙啊#滑稽

#include<bits/stdc++.h>
//#pragma GCC optimize(3)
using namespace std;
//int s[2000001];
int n,m;
unordered_map <int,int> s;
int main()
{
//__attribute__((optimize("-O3")))
//freopen("test.txt","r",stdin);
ios::sync_with_stdio(false);cin.tie(0);
cin>>n;
for(int i=0;i<n;i++)
{
int tmp;
cin>>tmp;
s[tmp]^=1;

}
int a=0,b;
for( unordered_map<int, int>::iterator iter = s.begin(); iter != s.end(); ++iter)
if(iter->second==1)
if(a==0)
a=iter->first;
else
b=iter->first;
if(a<=b)
cout<<a<<" "<<b;
else
cout<<b<<" "<<a;

}