#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
#define INF (int)1e9

int len, a[15];

int cww_search(bool used[]) {
  int ans = 0, tmp;
  for(int i = 0; i < len; i++) {
    if(used[i] == false) {
      used[i] = true;
      for(int j = i+1; j < len; j++) {
        if(used[j] == false && a[j] != a[i]) {
          used[j] = true;
          for(int k = j+1; k < len; k++) {
            if(used[k] == false && a[k] == a[j]) {
              used[k] = true;
              tmp =  100*a[i]+10*a[j]+a[k] + cww_search(used);
              if(ans < tmp) ans = tmp;
              used[k] = false;
            }
          }
          used[j] = false;
        }
      }
      used[i] = false;
    }
  }
  return ans;
}

int main(void) {
    string s;
    cin >> s;
    len = s.size();
    for(int i = 0; i < s.size(); i++) a[i] = int(s[i] - '0');
    bool used[15];
    fill(used, used + 15, false);
    cout << cww_search(used) << endl;
    return 0;
}