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

int main () {
	 ios::sync_with_stdio(false);
	 cin.tie(nullptr);
	 cout.tie(nullptr);
	 vector<int> v;
	 v.push_back(15); //insertion operation
	 v.push_back(10);
	 v.push_back(20);
	 //~ cout << v.size() << '\n'; //size of vector
	 //~ for (int i = 0; i < v.size(); i++) {
		 //~ cout << v[i] << ' ';
	 //~ }
	 //v.begin(); //beginning point
	 //v.end(); //ending point
	 //~ cout << "BEFORE SORTING : \n";
	 //~ for (int i = 0; i < v.size(); ++i) {
		 //~ cout << v[i] << ' ';
	 //~ }
	 sort(v.begin(),v.end()); //accending order
	 //~ cout << "\nAFTER SORTING : \n";
	 //~ for (int i = 0; i < v.size(); ++i) {
		 //~ cout << v[i] << ' ';
	 //~ }
	 //~ cout << "\nDECENDING ORDER\n";
	 //~ sort (v.rbegin(),v.rend()); //decending order
	 //~ for (int i = 0; i < v.size(); ++i) {
		 //~ cout << v[i] << ' ';
	 //~ }
	 //binary_search(starting_point,ending_point,x); // 0(x nai) , 1(x ache)
	 //~ int x = 11;
	 //~ int f = binary_search(v.begin(),v.end(),x); //time complexity = log2(n)
	 //~ cout << f << '\n';
	 //~ if (f == 1) {
		 //~ cout << "ACHE\n";
	 //~ } else {
		 //~ cout << "NAI\n";
	 //~ }
	 //upper_bound(starting_point,ending_point,x) //it will return imi greater value
	 //lower_bound(starting_point,ending_point,x) //it will return x if x is present otherwise upper_bound
	 //~ auto it = upper_bound(v.begin(),v.end(),20);
	 //~ if (it == v.end()) {
		 //~ cout << "YES\n";
	 //~ }
	 //10,15,20
	 //~ auto it = lower_bound(v.begin(),v.end(),21);
	 //~ if (it == v.end()) {
		 //~ cout << "YES\n";
	 //~ }
}