#include<bits/stdc++.h>
using namespace std;
#define maxx 100
char stacks[maxx],str[maxx];
int top=-1,v[maxx];
int push(char stacks[maxx],char c){
if(top==maxx)
return 0;
else
if(c==stacks[top]) return 0;
top++;
stacks[top]=c;
}
int pop(char stacks[maxx]){
if(top==-1)
return 0;
else
char x=stacks[top];
top--;
}
void srs(int i,int s,int c){
for(int j=0;j<s;j++){
if(top==-1){
push(stacks,str[j]);
}
else{
if(str[j]!=stacks[top]){
if(c==2){
pop(stacks);
}
push(stacks,str[j]);
c=1;
}
else{
c++;
if(c==2){
pop(stacks);
}
c=1;
}
}
}
}
void display (char stacks[])
{ int i;
if (top == -1)
printf ("Empty String");
else
{ for (i=0; i<=top; i++)
printf ("%c",stacks[i]);
}
printf ("\n");
}
int main(){
int s,z,c=1;
cin>>str;
s=strlen(str);
srs(0,s,c);
display(stacks);
}
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