// No.39 桁の数字を入れ替え
#include <iostream>
#include <string>
using namespace std;

int main() {
    string N;
    cin >> N;
    for (int i = 0; i < N.size(); ++i) {
        int x = -1;
        int cur = N[i];
        for (int j = N.size() - 1; j >= i + 1; --j) {
            if (cur < N[j]) {
                x = j;
                cur = N[j];
            }
        }
        if (x != -1) {
            swap(N[i], N[x]);
            break;
        }
    }
    cout << N << endl;
}