#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,h;
    cin>>n;
    h=n%10*10+n/10;
    int max=n;
	if (max<h){
		max=h;
	}
	cout<<max<<endl;
}
/**************************************************************
	Problem: 1734
	User: xiaojingxuan
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/