C++ :

#include<bits/stdc++.h>
using namespace std;
int main()
{
	int x,y;
	cin>>x;
	y=x%10*10+x/10%10;
	if(x>y) cout<<x;
	else cout<<y;
    return 0;
}

Java :

import java.util.Scanner;
public class Main
{   
	public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int x = sc.nextInt();
        int a = x/10;
        int b = x%10;
        int y = 10*b+a;
        if(x>y) {
        	System.out.println(x); 
        }else {
        	System.out.println(y); 
        }
        
    }
}