UVa 12027

#include <bits/stdc++.h>
#define ll long long

using namespace std;

int main()
{
 
 string a;
 while(cin>>a)
 {
  if(a=="0") break;
  int l,num;

  l=a.length();
  num=a[0]-'0';
  if(l>1 && l%2==0) num = num*10 + a[1]-'0';

  l = (l-1)/2;
  cout<<int(sqrt(num));

  for(int i=0; i<l; i++){
   cout<<0;
  }
  cout<<endl;
  
 }

 return 0;

}