#include <bits/stdc++.h> using namespace std; int main(){ string s; int n; cin >> s; while(s.size()%4!=0){ s='0'+s; } int l=s.size(); for(int i=0;i<l-3;i=i+4){ n=(s[i]-'0')*8+(s[i+1]-'0')*4+(s[i+2]-'0')*2+(s[i+3]-'0')*1; if(n<10){ cout<<n; }else{ cout<<(char)(n+'A'-10); } } return 0; }