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

	return 0;
}

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