#include<bits/stdc++.h>
#define REP(x,y,z) for(int x=y;x<=z;x++)
#define FORD(x,y,z) for(int x=y;x>=z;x--)
#define MSET(x,y) memset(x,y,sizeof(x))
#define FOR(x,y) for(__typeof(y.begin()) x=y.begin();x!=y.end();x++)
#define F first
#define S second
#define MP make_pair
#define PB push_back
#define SZ size()
#define M 
void RI(){}
template<typename... T>
void RI( int& head, T&... tail ) {
    scanf("%d",&head);
    RI(tail...);
}
using namespace std;
typedef long long LL;
int n;
string gen(int x, char st)
{
	while(st>'z') st-=26;
	if(x==0) {
		return "";
	}
	if(x==1) {
		string re = "";
		return re+st;
	}
	if(x==2) {
		string re="";
		re+=st;
		re+=st;
		return re;
	}

	string tmp = "";
	if(x%2)
	{
		tmp += st;
		return tmp + gen(x-1, st+1) + tmp;
	}
	else
	{
		int pw = 0;
		while(x%2==0) {
			x/=2;
			pw++;
		}

		REP(i,1,pw+1) tmp += st;
		return tmp + gen(x-1, st+1) + tmp;
	}
}
int main()
{
	while(~scanf("%d",&n))
	{
		cout << gen(n, 'a') << endl;
	}
	return 0;
}