#include <bits/stdc++.h>
using namespace std;

int main(){
    int n;
    cin>>n;
    int x = n % 10 * 10 + n / 10;
    if(n > x){
    	cout<<n;
	}else{
		cout<<x;
	}
}
 

/**************************************************************
	Problem: 1625
	User: admin
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/