#include <bits/stdc++.h>
using namespace std;

typedef long long LL; 
typedef pair<int, int> pii; 
typedef pair<LL, LL> pll; 
typedef pair<string, string> pss; 
typedef vector<int> vi; 
typedef vector<vi> vvi; 
typedef vector<pii> vii; 
typedef vector<LL> vl; 
typedef vector<vl> vvl;

int main(){
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	string a;
	cin >> a;
	int c = 0;
	int arr[a.length()];
	bool zeroflag = false;
	
	for(int i = 0; i <  a.length(); i++){
		c += a[i] - '0';
		arr[i] = a[i] - '0';
		if(a[i] == '0') zeroflag = true;
		
	}
	
	if(!zeroflag || c % 3 != 0){
		cout << "-1\n";
		return 0;
	}else{
		sort(arr, arr + a.length());
		for(int i = 0; i < a.length(); i++){
			cout << arr[a.length() - i - 1];
		}
		cout << "\n";
	}

	return 0;
}