import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;

public class No39 {

	public static void main(String[] args) throws IOException{
		//桁の数字を入れ替え
		String str = readStr()[0] , s;
		String[] N = str.split("") , clone;
		int max = Integer.parseInt(str);
		
		for(int i = 0;i < N.length;i++) {
			for(int j = i + 1;j < N.length;j++) {
				clone = N.clone();
				str = "";
				s = clone[j];
				clone[j] = clone[i];
				clone[i] = s;
				for(String c : clone) {
					str += c;
				}
				max = Math.max(max, Integer.parseInt(str));
			}
		}
		
		System.out.println(max);

	}
	
	public static String[] readStr() throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		ArrayList<String> list = new ArrayList<>();

		do {
			list.add(br.readLine());
		}while(br.ready());

		br.close();

		String[] text = new String[list.size()];
		list.toArray(text);

		return text;

	}

}