#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="020"+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<<c;
		else  cout<<(char)(c+'A'-10);
	
	}
	
	
	return 0;
}


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