#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <queue>
#include "math.h"
#include <complex>
#include <iomanip>
#include <map>
#define ifor(i,a,b) for (int i=(a);i<(b);i++)
#define rfor(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define rep(i,n) for (int i=0;i<(n);i++)
#define rrep(i,n) for (int i=(n)-1;i>=0;i--)
using namespace std;
typedef long double ld;
typedef long long int  lli;
typedef complex <double> P;
const double eps = 1e-11;
int vex[4]={1,0,-1,0};
int vey[4]={0,1,0,-1};
typedef vector<double> Vec;
typedef vector<int> vec;
typedef vector<Vec> MAT;
typedef vector<vec> mat;
lli MOD=1000000007;
int main(){
  lli N;
  cin >>N;
  int cnt=0;
 while(N>0){
   lli D = (lli)sqrt(N);
   N -=D*D;
   //cout<<N<<endl;
   rep(i,D-1)cout<<(char)('a'+cnt)<<(char)('a'+cnt+1);
   cout<<(char)('a'+cnt);
   cnt+=2;
 }
 cout << endl;
}