#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <string>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <cstring>

typedef long long ll;
using namespace std;

#define mod 1000003
#define INF 1000000000
#define LLINF 2000000000000000000LL

#define SIZE 100

string ans;

int add(int n,char a,char b){
    int N = n;
    
    ans+=a;
    
    if(n<4)
        return n-1;
    
    int c=4,i=2;
    
    while(1){
        ans+=b;
        ans+=a;
        
        if(c+i*2+1 <=n)
            c+=i*2+1;
        else
            break;
    }
    
    return n-c;
}

int main(){
    int n;
    
    scanf("%d",&n);
    
    for(int i=0;n>0;i+=2){
        
        n = add(n,'a'+(i%26),'a'+(i+1)%26);
        
    }
    
    cerr << n << endl;
    
    cout << ans << endl;
    
    return 0;
}