#include<bits/stdc++.h> using namespace std; char q[24],a[8]; int front=0,rear=0; void push(char x){ if(rear<24){ q[rear]=x; rear++; } } void pop(){ if(front != rear){ front++; } } char getFront(){ return q[front]; } int size(){ return rear-front; } int main(){ cin>>a; for(int i=0;i<strlen(a);i++){ push(a[i]); } int k=1; while(size()!=0){ if(k%2!=0){ cout<<getFront(); pop(); }else{ push(getFront()); pop(); push(getFront()); pop(); } k++; } return 0; }