#include<bits/stdc++.h>
using namespace std;
string t,s; 
int c;
int main(){
	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){
	t=s.substr(i,4);
	c=(t[0]-'0')*8+(t[1]-'0')*4+(t[2]-'0')*2+(t[3]-'0')*1;
	if(c>9){
		c=c+'A'-10;	
		cout<<(char)c;
	}else cout<<c;                                        

	}

    return 0;
}

/**************************************************************
	Problem: 1294
	User: zhangailin
	Language: C++
	Result: Accepted
	Time:11 ms
	Memory:2076 kb
****************************************************************/