#include <stdio.h>
#include <string.h>

char s[20];

void ReadData(void){
  FILE *f = fopen("NUMAR.IN","rt");
  fscanf(f,"%s",s);
  fclose(f);
}

void SortDigits(void){
  int sch;
  do{
    sch = 0;
    for (int i=0;i<strlen(s)-1;i++)
      if (s[i]>s[i+1]){
	char aux = s[i];
	s[i] = s[i+1];
	s[i+1] = aux;
	sch = 1;
      }
  }
  while (sch);
}

void FindFirstDigit(void){
  if (s[0] != '0')
    return;
  int k = 0;
  while (s[k] == '0')
    k++;
  s[0] = s[k];
  s[k] = '0';
}

void FindLastDigit(void){
  int k = strlen(s)-1;
  char lastDigit;
  lastDigit = s[k];
  while (k && (lastDigit & 1))
    lastDigit = s[--k];
  for (int j=k;k<strlen(s)-1;k++)
    s[k]=s[k+1];
  s[strlen(s)-1] = lastDigit;
}

void FindSolution(void){
  SortDigits();
  FindLastDigit();
  FindFirstDigit();
}

void WriteSolution(void){
  FILE *f=fopen("NUMAR.OUT","wt");
  if (s[strlen(s)-1] & 1)
    fprintf(f,"NU EXISTA\n");
  else
    fprintf(f,"%s\n",s);
  fclose(f);
}

void main(void){
  ReadData();
  FindSolution();
  WriteSolution();
}