#include <iostream>
#include <stack>

using namespace std;

int main(){
 stack<int> s;

 s.push(10);
 s.push(20);
 s.push(30);

 cout << "size:"<<s.size()<<endl;

 while(!s.empty())
 {
 cout<<s.top()<<endl;
	s.pop();
 }


 cout << "size:"<<s.size()<<endl;
 return 0;
}