import java.util.*;

public class Main{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    long n = scan.nextLong();
    String[] a = new String[]{"z","a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};
    ArrayList<String> g = new ArrayList<String>();
    while (n>0){
      long t1 = (long) n%26;
      int t = (int) t1;
      g.add(a[t]);
      if (t == 0){
        t = 26;
      }
      n -= t;
      n = (long) n/26;
    }
    for (int p = g.size()-1;p>=0;p--){
      System.out.print(g.get(p));
    }
    System.out.println("");
  }
} import java.util.*; util.* java public class Main{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    long n = scan.nextLong();
    String[] a = new String[]{"z","a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};
    ArrayList<String> g = new ArrayList<String>();
    while (n>0){
      long t1 = (long) n%26;
      int t = (int) t1;
      g.add(a[t]);
      if (t == 0){
        t = 26;
      }
      n -= t;
      n = (long) n/26;
    }
    for (int p = g.size()-1;p>=0;p--){
      System.out.print(g.get(p));
    }
    System.out.println("");
  }
} Main public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    long n = scan.nextLong();
    String[] a = new String[]{"z","a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};
    ArrayList<String> g = new ArrayList<String>();
    while (n>0){
      long t1 = (long) n%26;
      int t = (int) t1;
      g.add(a[t]);
      if (t == 0){
        t = 26;
      }
      n -= t;
      n = (long) n/26;
    }
    for (int p = g.size()-1;p>=0;p--){
      System.out.print(g.get(p));
    }
    System.out.println("");
  } main {
    Scanner scan = new Scanner(System.in);
    long n = scan.nextLong();
    String[] a = new String[]{"z","a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};
    ArrayList<String> g = new ArrayList<String>();
    while (n>0){
      long t1 = (long) n%26;
      int t = (int) t1;
      g.add(a[t]);
      if (t == 0){
        t = 26;
      }
      n -= t;
      n = (long) n/26;
    }
    for (int p = g.size()-1;p>=0;p--){
      System.out.print(g.get(p));
    }
    System.out.println("");
  } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) long n = scan.nextLong(); n scan.nextLong() scan.nextLong scan String[] a = new String[]{"z","a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"}; a new String[]{"z","a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"} ArrayList<String> g = new ArrayList<String>(); g new ArrayList<String>() while (n>0){
      long t1 = (long) n%26;
      int t = (int) t1;
      g.add(a[t]);
      if (t == 0){
        t = 26;
      }
      n -= t;
      n = (long) n/26;
    } n>0 n 0 {
      long t1 = (long) n%26;
      int t = (int) t1;
      g.add(a[t]);
      if (t == 0){
        t = 26;
      }
      n -= t;
      n = (long) n/26;
    } long t1 = (long) n%26; t1 (long) n%26 (long) n 26 int t = (int) t1; t (int) t1 g.add(a[t]) g.add g a[t] a t if (t == 0){
        t = 26;
      } t == 0 t 0 {
        t = 26;
      } t = 26 t 26 n -= t n t n = (long) n/26 n (long) n/26 (long) n 26 for (int p = g.size()-1;p>=0;p--){
      System.out.print(g.get(p));
    } int p = g.size()-1; int p = g.size()-1; p g.size()-1 g.size() g.size g 1 p>=0 p 0 p-- p-- p {
      System.out.print(g.get(p));
    } {
      System.out.print(g.get(p));
    } System.out.print(g.get(p)) System.out.print System.out System System.out g.get(p) g.get g p System.out.println("") System.out.println System.out System System.out "" String[] args args public class Main{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    long n = scan.nextLong();
    String[] a = new String[]{"z","a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};
    ArrayList<String> g = new ArrayList<String>();
    while (n>0){
      long t1 = (long) n%26;
      int t = (int) t1;
      g.add(a[t]);
      if (t == 0){
        t = 26;
      }
      n -= t;
      n = (long) n/26;
    }
    for (int p = g.size()-1;p>=0;p--){
      System.out.print(g.get(p));
    }
    System.out.println("");
  }
} public class Main{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    long n = scan.nextLong();
    String[] a = new String[]{"z","a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};
    ArrayList<String> g = new ArrayList<String>();
    while (n>0){
      long t1 = (long) n%26;
      int t = (int) t1;
      g.add(a[t]);
      if (t == 0){
        t = 26;
      }
      n -= t;
      n = (long) n/26;
    }
    for (int p = g.size()-1;p>=0;p--){
      System.out.print(g.get(p));
    }
    System.out.println("");
  }
} Main
import java.util.*;

public class Main{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    long n = scan.nextLong();
    String[] a = new String[]{"z","a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};
    ArrayList<String> g = new ArrayList<String>();
    while (n>0){
      long t1 = (long) n%26;
      int t = (int) t1;
      g.add(a[t]);
      if (t == 0){
        t = 26;
      }
      n -= t;
      n = (long) n/26;
    }
    for (int p = g.size()-1;p>=0;p--){
      System.out.print(g.get(p));
    }
    System.out.println("");
  }
}
