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

#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define repi(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define all(x) (x).begin(),(x).end()
#define foreach(u,v) for(auto (u) : (v))
#define pb push_back
#define mp make_pair
#define mt make_tuple

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<ll, ll> pll;
typedef vector<ll> vl;

const int inf = 1e9;
const ll linf = 1LL<<60;
const ll mod = 1e9 + 7;
const double eps = 1e-9;

/*
*/
string s;
int n;

int dfs(int used)
{
  int res = 0;
  rep(i, n) repi(j, i+1, n) repi(k, j+1, n){
    if(used>>i&1 or used>>j&1 or used>>k&1 or s[i]=='0' or s[i]==s[j] or s[j]!=s[k]) continue;
    int t = (s[i]-'0')*100+(s[j]-'0')*11+dfs(used|1<<i|1<<j|1<<k);
    res = max(res, t);
  }
  return res;
}

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

  cout << dfs(0) << endl;

  return 0;
}