#include<bits/stdc++.h>
using namespace std;
int main(){
   int n;
   cin>>n;
   int g=n/1%10;
   int s=n/10%10;
   int f=g*10+s;
   if(f>n){
   	cout<<f;
   }
   else cout<<n;
	return 0;
}

/**************************************************************
	Problem: 1625
	User: duyahan
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/