#include <iostream>
using namespace std;
int main() {
	int i,a,b,n;
	cin>>i;
	a=i/10;
	b=i%10;
	n=b*10+a;
	if(i>n){
		cout<<i; 
	}else{
		cout<<n;
	}
}
/**************************************************************
	Problem: 1734
	User: panyuchen
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/