#include<bits/stdc++.h>
using namespace std;
string s,t;
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) cout<<(char)(c+'A'-10);
		else cout<<c;
	}



	return 0;
}

/**************************************************************
	Problem: 1294
	User: wuhanyu
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2076 kb
****************************************************************/