#include <bits/stdc++.h>
using namespace std;

int main() {
	long long n, m = 26;
	cin >> n;
	string s = "";
	while(n > 0) {
		int mod = (n-1) % 26;
		s = " " + s;
		s[0] = ('a' + mod);
		n = (n-1) / m;
	}
	cout << s << "\n"; 
	return 0;
}
