#include <bits/stdc++.h> using namespace std; int n; string solve(); int main() { cin >> n; cout << solve() << endl; return 0; } string solve() { string res = "z"; int nxt = 0; for(int i = 62 - __builtin_clzll(n); i >= 0; --i) { res = res[0] + res + res[0]; if(n >> i & 1) { string tmp; tmp += (char)('a' + nxt); res = tmp + res + tmp; (++nxt) %= 26; } } return res; }