#include #include #include using namespace std; int main(){ long long n;cin>>n; if(n==0){ cout << "A" << endl; return 0; } string s; while(n != 0){ s.push_back('A'+n%26); n/=26; } reverse(s.begin(),s.end()); if(s.size()!=1)s[0]--; cout << s << endl; }