PAIRSTL

/*i am not gonna
lose this time*/

#include <bits/stdc++.h>
using namespace std;

#define fast ios_base::sync_with_stdio(0);cin.tie(NULL);cout.tie(NULL)

#define ll long long
#define ull unsigned long long
#define INF INT_MAX
#define INM INT_MIN

#define mp make_pair
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define F first
#define S second

#define st(x) x.begin(),x.end()
#define sz(x) (int)(x).size()
#define bitcount(x) __builtin_popcountll(x)

#define f(i,n) for(int i=0;i<n;i++)
#define f1(i,n) for(int i=1;i<=n;i++)

int main()
{
    fast;
    /* pair <string,double> PAIR2  ("GeeksForGeeks", 1.23);
      cout << PAIR2.first << " " ;
    cout << PAIR2.second << endl ;

     PAIR3 = make_pair ("GeeksForGeeks is Best",4.56);
      g2.first = ".com";
    g2.second = 2;

    pair <string, int> g3(g2);*/

     pair<ll,ll>ar[n];  //declaration of pair of array;
     vector<pair<int,int>>v(n);  //declaration of pair of vectors

  for(int i=0;i<n;i++){
  cin>>a>>b;
  ar[i].first=a;
  ar[i].second=b;
   v[i]=make_pair(a,b);
   v[i]={a,b};
  v.push_back(make_pair(a,b));
  }

 vector<pair<int,int>>v{{1,2},{2,3}};
 //PRINTING VECTOR AND ARRAY PAIRS
vector<pair<int,int>>::iterator it;

for(it=v.begin();it!=v.end();it++)
cout<<it->first<<" "<<it->second<<" ";

 for(auto it:v)
 cout<<it.first<<" "<<it.second<<" ";

 for(auto i=0;i<v.size();i++)
 cout<<v[i].first<<" "<<v[i].second<<" ";

 for(int i=0;i<n;i++){
        cout<<ar[i].first<<"  ";
        cout<<ar[i].second<<" ";
 }

     pair1.swap(pair2); //swap pair values

//SORT PAIR
sort(v.begin(),v.end());  //sort by first elements
sort(v.begin(),v.end(),sortbysec);
bool sortbysec(pair<int,int> a,pair<int,int> b)
{
        return b.second>a.second;
}


  return 0;
}