#include<bits/stdc++.h>
using namespace std;
struct Point{
    int a;
    int b;

    bool operator < (const Point &po) const{//运算符重载
        if(this -> a < po.a){
            return true;
        }else if(this -> a == po.a){
            return this -> b < po.b;
        }else{
            return false;
        }
    }
};
int flag [35][35] = {0};//标记数组 用于判重

vector<Point> vec;
int main(){
    int n;
    cin >> n;
    int a[n];
    for(int i = 0;i < n;i++){
        cin  >> a[i];
    }
    for(int i = 0;i < n;i++){
        int n1 = a[i];
        for(int j = 0; j < n;j++){
            if(j == i) continue;
            int n2 = a[j];
            if(flag[n1][n2] == 0){//之前该点没出现过
                flag[n1][n2] = 1;
                Point p = {n1,n2};
                vec.push_back(p);
            }
        }
    }
    sort(vec.begin(),vec.end());
    int len = vec.size();
    for(int i = 0;i < le...