#include <bits/stdc++.h>

using namespace std;

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

typedef long long ll;

string T;
int N;

int dfs(int S) {
  int ret = 0;
  rep(i, N) {
    if(S >> i & 1) continue;
    REP(j, i+1, N) {
      if(S >> j & 1) continue;
      REP(k, j+1, N) {
        if(S >> k & 1) continue;
        int I = T[i] - '0';
        int J = T[j] - '0';
        int K = T[k] - '0';
        if(I != 0 && I != J && J == K)
          ret = max(ret, dfs(S^(1<<i)^(1<<j)^(1<<k)) + I * 100 + J * 10 + K);
      }
    }
  }
  return ret;
}

int main() {

  cin >> T;
  N = T.size();
  ll n = stoll(T);
  assert(1 <= n && n <= ll(1e12));

  cout << dfs(0) << endl;
  
  return 0;
}