#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cctype>
#include <vector>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <cmath>
#include <algorithm>
#include <string>
#include <iostream>  
#include <algorithm>  
#include <string>    
using namespace std; 
int convert(string str) 
{
    int sum=0;
    for(int i=0;i<str.length();i++)
    {
    	sum=sum*10+str[i]-‘0‘;
	}
	return sum;
}
int main()  
{  
    string str;
    cin>>str;
    int sum=convert(str);
	if(str.find("0")!=string::npos)
	{
		if(sum%3==0)
		{
			sort(str.begin(), str.end(), greater<char>());
			cout<<convert(str)<<" ";
		}  
		else
		cout<<-1<<" ";
	}
	else
	{
		cout<<-1<<" ";
	}
	return 0;
}