#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;

int N;

int main(){
    cin >> N;
    int k = 0;
    string ans;
    while(N > 0){
        int m = 0;
        while((m + 2ll)*(m + 2ll) / 4 <= N)
            ++m;
        rep(i, m)
            ans += 'a' + k + (i & 1);
        k += 2;
        N -= (m + 1ll)*(m + 1ll) / 4;
    }
    printf("%s\n", ans.c_str());
}