#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n);i++)
#define sz(x) int(x.size())
typedef long long ll;
typedef pair<int,int> P;

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

  int res = stoi(s);

  for (int bit = 3; bit < (1 << n); bit++) {
    int cnt = __builtin_popcount(bit);
    if (cnt != 2) continue;
    vector<int> tmp;
    for (int j = 0; j < n; j++) if (bit & (1<<j)) tmp.push_back(j);

    auto make_string = [&](int x,int y){
      string t = "";
      rep(i,n) {
        if (i == x) t += s[y];
        else if (i == y) t += s[x];
        else t += s[i]; 
      }
      return t;
    };

    string ns = make_string(tmp[0],tmp[1]);
    res = max(res,stoi(ns));
  }
  cout << res << endl;
  return 0;
}