STACK

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <cmath>
#include <queue>
#include <set> 
#include <map>
#include <stack>
using namespace std;
#define  pi acos(-1.0)
#define ll long long 
#define P pair<ll,ll>
#define pu push_back
const ll inf = 1e12+100;
const int N =2e3+100;
stack<int>s;
int main()
{
    for(int i =1;i<=5;i++) s.push(i);
    printf("%d\n",s.size());
    while(!s.empty()){
        int u =s.top();
        s.pop();
        printf("%d ",u);
    }
}

5
5 4 3 2 1