#include <iostream.h>
#include <stdio.h>
#include <string.h>
int main()
{ int i,n=1,min,t,p;
char a[100]="1111111110\0";
min=strlen(a)+1;
t=strlen(a);
if (t<2)
{puts(a);
return 1;
}
for (i=0;i<t-1;i++)
if (a[i]==a[i+1])
n++;
else
{if (n<min) {min=n;
p=i;}

n=1;
}
if (n<min) {min=n;p=strlen(a)-1;}
for (i=p;i>=p-min+1;i--)
cout<<a[i];
cout<<endl;

return 0;
}