#include<bits/stdc++.h> using namespace std; string s; int main(){ int n; cin>>s; while((s.size()%4!=0)){ s='0'+s; } for(int i=0;i<s.size()-2;i+=4){ n=(s[i]-'0')*8+(s[i+1]-'0')*4+(s[i+2]-'0')*2+(s[i+3]-'0')*1; if(n<=9){ cout<<n; }else{ cout<<(char)(n+'A'-10); } } return 0; }