#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: huanghengyi
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/