#include<bits/stdc++.h>
using namespace std;
int main(){
    string s,s1,n="0123456789ABCDEF";
    cin>>s;
    if(s.size()%4==1)  s="000"+s;
    else if(s.size()%4==2)  s="00"+s;
    else if(s.size()%4==2)  s="0"+s;
    for(int i=0;i<s.size();i=i+4){
        s1=s.substr(i,4);
        cout<<n[(s1[0]-'0')*8+(s1[1]-'0')*4+(s1[2]-'0')*2+(s1[3]-'0')*1];
    }
    return 0;
}


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