#include "bits/stdc++.h"
using namespace std;
#define int long long
#define FOR(i, a, b) for(int i=(a);i<(b);i++)
#define RFOR(i, a, b) for(int i=(b-1);i>=(a);i--)
#define REP(i, n) for(int i=0; i<(n); i++)
#define RREP(i, n) for(int i=(n-1); i>=0; i--)
#define ALL(a) (a).begin(),(a).end()
#define UNIQUE_SORT(l) sort(ALL(l)); l.erase(unique(ALL(l)), l.end());
#define CONTAIN(a, b) find(ALL(a), (b)) != (a).end()
#define array2(type, x, y) array<array<type, y>, x>
#define vector2(type) vector<vector<type> >
#define out(...) printf(__VA_ARGS__)

int dxy[] = {0, 1, 0, -1, 0};

/*================================*/

string N;

map<int, int> M;

signed main()
{
#if DEBUG
    std::ifstream in("input.txt");
    std::cin.rdbuf(in.rdbuf());
#endif
    cin>>N;
    
    for (auto c : N) M[c-'0']++;
    
    if (M.size()==1) {
        cout << N << endl;
    }
    else {
        int ans = 1;
        int keySum = 0;
        for (auto it = M.begin(); it != M.end(); it++) {
            keySum += it->first * it->second;
        }
        RFOR(mod,1,10) {
            int cnt = 0;
            for (auto it = M.begin(); it != M.end(); it++) {
                if (it->first%mod==0) cnt++;
            }
            if (cnt == M.size()) {
                ans *= mod;
                break;
            }
        }
        if (keySum%9==0 && ans%9) ans *= 9;
        else if (keySum%3==0 && ans%3) ans *= 3;
        cout << ans << endl;
    }
    
    return 0;
}