#include <iostream>
#include <algorithm>
using namespace std;

int main()
{
 freopen("BAI07.INP","r",stdin);
 freopen("BAI07.OUT","w",stdout);
 string n;
 cin >> n;
 int l = n.length();
 sort(n.begin(),n.end(),greater<char>());
 if (n[l-1] == '0')
 {
  int t = 0;
  for (int i = 0;i < l;i++)
   t += n[i] - 48;
  if (t % 3 == 0)
   cout << n;
  else
   cout << -1;
 }
 else
  cout << -1;
}

#include<bits/stdc++.h>
using namespace std;
int main()
{
 string s,s1;
 bool f=true;
 int t=0;
 cin>>s;
 for (int i=0;i<s.length();i++)
 {
  int z=s[i]-'0';
  t+=z;
  if (s[i]=='0'&&f==true) f=false;
  else s1=s1+s[i];
 }
 if (t%3==0&&f==false) cout<<s1<<0;
 else cout<<-1;
}