#include <iostream>
#include <string>
using namespace std;

#define NUM(A) (int)(A) - (int)'0'
#define FOR(i,s,e) for(int i = (s);i <= (e);i++)
#define R_FOR(i,s,e) for(int i = (s);i >= (e);i--)
string S;

int N;

int val[9];

int res = 0;

int main()
{
	cin >> res;
	S = to_string(res);
	N = S.size();
	FOR(i,0,N - 1)
	{
		val[i] = NUM(S[i]);
	}

	FOR(i,0,N - 1)
	{
		FOR(j,i + 1,N - 1)
		{
			int temp = 0;
			FOR(k,0,N - 1)
			{
				if(i == k)
				{
					temp = temp * 10 + val[j];
				}
				else if(j == k)
				{
					temp = temp * 10 + val[i];
				}
				else
				{
					temp = temp * 10 + val[k];
				}
			}
			res = max(res,temp);
		}
	}
	cout << res << endl;
	return 0;
}