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