#include<bits/stdc++.h> using namespace std; int n,a,sum=0; int main(){ string s; long long 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; }