#include<bits/stdc++.h>
using namespace std;
int main(){
	string s,s1;
	int t;
	cin>>s;
	if(s.size()%4==1) s="000"+s;
	else if(s.size()%4==2) s="00"+s;
	else if(s.size()%4==3) s="0"+s;
	for(int i=0;i<s.size();i=i+4){
		s1=s.substr(i,4);
		t=(s1[3]-48)*1+(s1[2]-48)*2+(s1[1]-48)*4+(s1[0]-48)*8;
		if(t>9){
			cout<<char(t+55);
		}else{
			cout<<t;
		}
	}
	return 0;
}

/**************************************************************
	Problem: 1294
	User: zengyixuan
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2076 kb
****************************************************************/