#include <bits/stdc++.h>
using namespace std;

int main(){
	char maxL,c;
    maxL='0';
	while(cin>>c){  //8B01
	   if(c>maxL) maxL=c;
	}
	if(maxL>='0' &&maxL<='9') cout<<maxL-'0'+1;
	 else cout<<maxL-'A'+11;
	return 0;
}