#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;

#define ipow(a,b)+0.5 (int)pow(a,b)
#define pb push_back
#define mp make_pair
#define mod 1000000007
#define fi first
#define se second

#define rep(i,n) for(int i=0;i<n;i++)
#define reps(i,a,b) for(int i=a;i<=b;i++)

string s;
bool vis[100005]={false};
int b[100005];
multiset<int>re;
map<int,int>ret;
vector<int>store[100005];
multiset<int>rem[3];

class Task
{
public:
    void solve(istream& in,ostream& out)
    {
          in>>s;
          ll S=sum();

          int n=s.length();
          bool flag=false;
          int y=0;

          rep(i,n)
          {
               b[i]=s[i]-48;
               if(ret.find(b[i])==ret.end())
               {
                     ret.insert(mp(b[i],y));
                     store[y].push_back(i);
                     y++;
               }
               else
               {
                     int k=(*ret.find(b[i])).se;
                     store[k].pb(i);
               }
          }

          sort(b,b+n);
          int store=-182;

          if(S%3==0)
          out<<s;
          else
          {
               for(int i=0;i<n;i++)
               {
                    if(b[i]%3==0)
                    rem[0].insert(b[i]);
                    else if (b[i]%3==1)
                    rem[1].insert(b[i]);
                    else
                    rem[2].insert(b[i]);
               }

               if(S%3==1)
               {
                    if(rem[1].size()>0)
                    {
                         re.insert(*rem[1].begin());
                         flag=true;
                    }
               }

               else if (S%3==2)
               {
                    if(rem[2].size()>0)
                    {
                         re.insert(*rem[2].begin());
                         flag=true;
                    }
                    else if (rem[1].size()>=2)
                    {
                         re.insert(*rem[1].begin());
                         re.insert(*next(rem[1].begin()));
                         flag=true;
                    }
               }

               if(!flag)
               out<<-1<<endl;
               else
               {
                    if(re.size()==1)
                    {
                         auto it = re.begin();
                         int k=(*ret.find(*it)).se;
                         int c1=store[k][0];
                         vis[c1]=true;
                    }

                    else
                    {
                         auto it=re.begin();
                         if(*it==(*next(it)))
                         {
                              auto it = re.begin();
                              int k=(*ret.find(*it)).se;
                              vis[store[k][0]]=true;
                              vis[store[k][1]]=true;
                         }
                    }

                    leading(n);

                    for(int i=0;i<n;i++)
                    {
                         if(!vis[i])
                         out<<s[i];
                    }

                    out<<endl;
               }
          }
    }

    void leading(int n)
    {
          if(vis[0]==false)
          return ;
          else
          {
               reps(i,1,n-1)
               {
                    if(s[i]=='0')
                    vis[i]=true;
                    else
                    break;
               }
          }
    }

    ll sum()
    {
          ll res=0;
          int n=s.length();

          rep(i,n)
          {
               res+=s[i]-48;
          }

          return res;
    }
};


int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    Task solver;
    std::istream& in(std::cin);
    std::ostream& out(std::cout);
    solver.solve(in,out);
    out.flush();

      return 0;
}