#include <bits/stdc++.h>
using namespace std;
int main(){
    int n,s=0,g=0;
	cin>>n; 
	s=n/10;
	g=n%10;
	if(s>g)
	    cout<<s<<endl;
    else
        cout<<g<<endl;
}
/**************************************************************
	Problem: 1622
	User: wngjinming
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/