#include<iostream.h>
#include<string.h>
void main()
{ char s[200];
 int i=0;
 cin>>s;
 while(i<strlen(s)-1)
 { if(s[i]==s[i+1])
   { strcpy(s+i,s+i+2);
     if(i>0) i=i-1;
   }
   else i++;
 }
 cout<<s;
 }