#include <bits/stdc++.h>


int main() {

  int N;
  int p[10] = {
    1,
    10,
    100,
    1000,
    10000,
    100000,
    1000000,
    10000000,
    100000000,
    1000000000
  };
  int S;
  int temp;
  int a, b;
  int ans = -1;
  
  std::cin >> N;
  ans = N;

  temp = N;
  S = 0;
  while( temp != 0 ) {
    S += 1;
    temp /= 10;
  }

  for(int i = 0; i < S; ++i) {
    for(int j = i+1; j < S; ++j) {
      temp = N;
      a = (N / p[i]) % 10;
      b = (N / p[j]) % 10;
      temp -= a * p[i];
      temp -= b * p[j];
      temp += b * p[i];
      temp += a * p[j];
      ans = std::max(ans, temp);
    }
  }

  std::cout << ans << std::endl;
  
  return 0;
}