#include <bits/stdc++.h>

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

using namespace std;

int main(){
	string s; cin>>s;

	if(count(s.begin(),s.end(),s[0])==s.length()){
		cout<<s<<'\n';
		return 0;
	}

	sort(s.begin(),s.end());

	int g=0;
	if(s.length()<9) g=stoi(s);

	s.erase(unique(s.begin(),s.end()),s.end());

	rep(i,s.length()) rep(j,s.length()) {
		int a=s[i]-'0',b=s[j]-'0';
		g=gcd(g,9*(a+b));
	}
	cout<<g<<'\n';

	return 0;
}