#include<bits/stdc++.h>
using namespace std;
int main(){
	int a,b,c,d;
	cin>>a;
	c=a%10;
	d=a/10%10;
	b=c*10+d;
	if(b>a){
		cout<<b;
	}
	if(b<a){
		cout<<a;
	}
}
/**************************************************************
	Problem: 1625
	User: toughuatao1
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/