#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <set>
using namespace std;

int main(){
	int n;
	cin >> n;

	long long lb = 0;
	long long ub = 100000;
	while(ub-lb > 1){
		long long mid = (lb+ub)/2;
		if( n - (mid-1)*(mid-1)/4 > 50000){
			lb = mid;
		}else{
			ub  =mid;
		}
	}

	long long ababababa = lb;
	string ans = "";
	for(int i=0; i<ababababa; i++){
		ans.push_back(i?'a':'b');
	}
	long long rem = n - (ababababa-1)*(ababababa-1)/4;
	for(int i=0; i<rem; i++){
		ans.push_back('c' + i%20);
	}

	cout << ans << endl;

	return 0;
}