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

int main(){
    string S;
    cin >> S;

    ll ans = 0;
    for (int i = 0; i < S.size(); i++){
        for (int j = i+1; j < S.size(); j++){
            string s = S;
            swap(s[i], s[j]);
            ans = max(ans, stoll(s));
        }
    }

    cout << ans << endl;
}