#include <bits/stdc++.h>
using namespace std;
char cuv[301][301],s[301],*p,aux[300];
int n,k;

int main()
{
   cin.getline(s,300);
   ///eliminat toate carcaterele diferite de spatiu si litere
   for(int i=0;s[i];i++)
    if((s[i]==' ' && s[i-1]!=' ')||(s[i]>='a'&& s[i]<='z') ||(s[i]>='A'&&s[i]<='Z'))
    aux[k++]=s[i];
   aux[k]=NULL;
   strcpy(s,aux);
   ///impartire in cuvinte
   p=strtok(s," ");
   while(p)
   {
       strcpy(cuv[++n],p);
       p=strtok(NULL," ");
   }
   ///afisare
   for(int i=1;i<=n/2;i++)
    cout<<cuv[i]<<'\n'<<cuv[n-i+1]<<'\n';
   if(n%2==1) cout<<cuv[n/2+1];
   return 0;
}