#include <iostream>

using namespace std;

int n,v[999999];
char x[999999];

int modul(int dif){
    if(dif < 0)
   {
       dif = -dif;
       return dif;
   }
return dif;
}

void print(){
    for(int i = 1; i<=n; i++)
    {
        x[i] = 97 + v[i];
        cout << x[i];
    }
    cout << endl;
}


void bak(int k){
    for(int i = 0; i<=n/2; i++){
            v[k] = i;
        if(v[1] == 0 && (k == 1 || modul(v[k]- v[k-1])== 1))
            if(k == n){
                if(v[n] == 0) print();
            }
            else
                bak(k+1);

    }
}

int main(){
    cin >> n;
    bak(1);
}