#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <algorithm>
#include <sstream>
#include <map>
#include <set>
using namespace std;


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

typedef long long ll;
typedef unsigned long long ull;
typedef long double lb;

/* ここからが本編 */
int main(void)
{
   int i,j,k;
   char n[10];
   char *max,*min;
   cin >> n;
   char nagasa;
   nagasa = strlen(n)-1;
   max = &n[nagasa];

   i = nagasa;
   for(j = 0; j < i; j++) {
      if(n[j] < n[i]) {
         min = &n[j]; max = &n[i]; break;
      }
   }
   for(i = nagasa - 1; i > -1; i--) {
      if(*max < n[i]) {
         for(j = 0; j < i; j++) {
            if(n[j] < n[i]) {
               min = &n[j]; max = &n[i]; break;
            }
         }
      }
   }
   if(max > min) swap(*max,*min);
   printf("%s\n",n);
   return 0;
}