https://pintia.cn/problem-sets/994805260223102976/problems

#include<iostream>
#include<stack>
#include<algorithm>

using namespace std ;
stack < string >  st ;

int main()
{
    string s ;
    while( cin >> s)
        st.push(s);
    cout <<st.top(); 
    st.pop();
    while(!st.empty() )
    {
        cout << " ";
        cout << st.top();
        st.pop();
    }
    return 0;
}