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

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