#define _USE_MATH_DEFINES
#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <complex>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
#include <iterator>
using namespace std;

int gcd(int a, int b){
    while(b != 0){
        int tmp = a % b;
        a = b;
        b = tmp;
    }
    return a;
}

int main()
{
    string s;
    cin >> s;
    int n = s.size();

    if(s == string(n, s[0])){
        cout << s << endl;
        return 0;
    }

    int x = 8;
    int y = 5;
    int z = 0;
    for(int i=0; i<n; ++i){
        x = gcd(x, s[i] - '0');
        y = gcd(y, s[i] - '0');
        z += s[i] - '0';
    }

    int ans = x * y;
    if(z % 9 == 0)
        ans *= 9;
    else if(z % 3 == 0)
        ans *= 3;
    cout << ans << endl;

    return 0;
}