import java.util.*;

class Main
{
  public static void main(String args[])
  {
    Scanner sc=new Scanner(System.in);
    long n=sc.nextLong();
    StringBuilder sb=new StringBuilder();
    while(n>0)
    {
      if(n%26==0)
      {
        sb.append('z');
        n=n/26-1;
      }
      else
      {
        sb.append((char)(n%26+96));
        n/=26;
      }
    }
    System.out.println(sb.reverse());
  }
} import java.util.*; util.* java class Main
{
  public static void main(String args[])
  {
    Scanner sc=new Scanner(System.in);
    long n=sc.nextLong();
    StringBuilder sb=new StringBuilder();
    while(n>0)
    {
      if(n%26==0)
      {
        sb.append('z');
        n=n/26-1;
      }
      else
      {
        sb.append((char)(n%26+96));
        n/=26;
      }
    }
    System.out.println(sb.reverse());
  }
} Main public static void main(String args[])
  {
    Scanner sc=new Scanner(System.in);
    long n=sc.nextLong();
    StringBuilder sb=new StringBuilder();
    while(n>0)
    {
      if(n%26==0)
      {
        sb.append('z');
        n=n/26-1;
      }
      else
      {
        sb.append((char)(n%26+96));
        n/=26;
      }
    }
    System.out.println(sb.reverse());
  } main {
    Scanner sc=new Scanner(System.in);
    long n=sc.nextLong();
    StringBuilder sb=new StringBuilder();
    while(n>0)
    {
      if(n%26==0)
      {
        sb.append('z');
        n=n/26-1;
      }
      else
      {
        sb.append((char)(n%26+96));
        n/=26;
      }
    }
    System.out.println(sb.reverse());
  } Scanner sc=new Scanner(System.in); sc new Scanner(System.in) long n=sc.nextLong(); n sc.nextLong() sc.nextLong sc StringBuilder sb=new StringBuilder(); sb new StringBuilder() while(n>0)
    {
      if(n%26==0)
      {
        sb.append('z');
        n=n/26-1;
      }
      else
      {
        sb.append((char)(n%26+96));
        n/=26;
      }
    } n>0 n 0 {
      if(n%26==0)
      {
        sb.append('z');
        n=n/26-1;
      }
      else
      {
        sb.append((char)(n%26+96));
        n/=26;
      }
    } if(n%26==0)
      {
        sb.append('z');
        n=n/26-1;
      }
      else
      {
        sb.append((char)(n%26+96));
        n/=26;
      } n%26==0 n%26 n 26 0 {
        sb.append('z');
        n=n/26-1;
      } sb.append('z') sb.append sb 'z' n=n/26-1 n n/26-1 n/26 n 26 1 {
        sb.append((char)(n%26+96));
        n/=26;
      } sb.append((char)(n%26+96)) sb.append sb (char)(n%26+96) n%26 n 26 96 n/=26 n 26 System.out.println(sb.reverse()) System.out.println System.out System System.out sb.reverse() sb.reverse sb String args[] args
import java.util.*;

class Main
{
  public static void main(String args[])
  {
    Scanner sc=new Scanner(System.in);
    long n=sc.nextLong();
    StringBuilder sb=new StringBuilder();
    while(n>0)
    {
      if(n%26==0)
      {
        sb.append('z');
        n=n/26-1;
      }
      else
      {
        sb.append((char)(n%26+96));
        n/=26;
      }
    }
    System.out.println(sb.reverse());
  }
}