#include <iostream>
#include <stack>

using namespace std;

int main(void){
    stack<string> container;
    string strs[]={"hello", " world!"};
    for(int i=0;i<2;i++){
        container.push(strs[i]);
    }
    while(!container.empty()){
        cout <<  container.top()<<endl;
        container.pop();
    }
    return 0;
}