#include<iostream.h>
#include<string.h>

struct nod
{ char info;
  nod *prec, *urm;
};
nod *prim;

void adaugs(nod *&prim, char x)
{ nod *p, *nou;
  if(prim)
    { p=prim;
      while(p->urm) p=p->urm;
      nou=new nod;
      nou->info=x;
      p->urm=nou;
      nou->prec=p;
      nou->urm=0;
    }
  else
    {  prim=new nod;
       prim->info=x;
       prim->urm=0;
       prim->prec=0;
    }
}

void afis(nod *prim)
{  nod *p=prim;
   while(p->urm) p=p->urm;
   while(p)
     { cout<<p->info;
       p=p->prec;
     }
}

void main()
{ char s[30];
  cin>>s;
  for(int i=0;i<strlen(s); i++) adaugs(prim,s[i]);
  afis(prim);
}