#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int Max = n;
  if (n / 10 > Max) Max = n / 10;
  if (n % 10 + (n / 100) * 10 > Max) Max = n % 10 + (n / 100) * 10;
  cout << Max;
}
