#include<bits/stdc++.h>
using namespace std;
int main(){
    string s,s1;
    int t=0;
    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: fuyijun
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2076 kb
****************************************************************/