#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <list>
#define INF 99999999;
using namespace std;


int main(int argc, const char * argv[]) {
    string N;
    cin >> N;
    string tmp;
    int max = 0;
    int pos = 0;
    for (int i = 0; i < N.size(); i++) {
        if (max <= N[i] ) {
            max = N[i];
            pos = i;
        }
    }
    for (int i = 0; i < N.size(); i++) {
        if(max != N[i]){
            swap(N[i], N[pos]);
        }
    }
       cout << N << endl;
}