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


	return 0;
}

/**************************************************************
	Problem: 1625
	User: wuzihang
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/