import java.util.*;

public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);

    long pre_total = 0;
    long total = 0;
    int mojisuu = 0;

    long n = sc.nextLong();
    StringBuilder val = new StringBuilder();


    while(n>0){
      val.append(alpha((int)((n-1)%26)));
      n = (n-1) /26;
    }




      //0x61 = ９７ = a

      System.out.println(val.reverse());
    }








  static char alpha(int n){
      return (char)(n+97);
  }
} import java.util.*; util.* java public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);

    long pre_total = 0;
    long total = 0;
    int mojisuu = 0;

    long n = sc.nextLong();
    StringBuilder val = new StringBuilder();


    while(n>0){
      val.append(alpha((int)((n-1)%26)));
      n = (n-1) /26;
    }




      //0x61 = ９７ = a

      System.out.println(val.reverse());
    }








  static char alpha(int n){
      return (char)(n+97);
  }
} Main public static void main(String[] args){
    Scanner sc = new Scanner(System.in);

    long pre_total = 0;
    long total = 0;
    int mojisuu = 0;

    long n = sc.nextLong();
    StringBuilder val = new StringBuilder();


    while(n>0){
      val.append(alpha((int)((n-1)%26)));
      n = (n-1) /26;
    }




      //0x61 = ９７ = a

      System.out.println(val.reverse());
    } main {
    Scanner sc = new Scanner(System.in);

    long pre_total = 0;
    long total = 0;
    int mojisuu = 0;

    long n = sc.nextLong();
    StringBuilder val = new StringBuilder();


    while(n>0){
      val.append(alpha((int)((n-1)%26)));
      n = (n-1) /26;
    }




      //0x61 = ９７ = a

      System.out.println(val.reverse());
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long pre_total = 0; pre_total 0 long total = 0; total 0 int mojisuu = 0; mojisuu 0 long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc StringBuilder val = new StringBuilder(); val new StringBuilder() while(n>0){
      val.append(alpha((int)((n-1)%26)));
      n = (n-1) /26;
    } n>0 n 0 {
      val.append(alpha((int)((n-1)%26)));
      n = (n-1) /26;
    } val.append(alpha((int)((n-1)%26))) val.append val alpha((int)((n-1)%26)) alpha (int)((n-1)%26) (n-1) n 1 26 n = (n-1) /26 n (n-1) /26 (n-1) n 1 26 System.out.println(val.reverse()) System.out.println System.out System System.out val.reverse() val.reverse val String[] args args static char alpha(int n){
      return (char)(n+97);
  } alpha {
      return (char)(n+97);
  } return (char)(n+97); (char)(n+97) n 97 int n n public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);

    long pre_total = 0;
    long total = 0;
    int mojisuu = 0;

    long n = sc.nextLong();
    StringBuilder val = new StringBuilder();


    while(n>0){
      val.append(alpha((int)((n-1)%26)));
      n = (n-1) /26;
    }




      //0x61 = ９７ = a

      System.out.println(val.reverse());
    }








  static char alpha(int n){
      return (char)(n+97);
  }
} public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);

    long pre_total = 0;
    long total = 0;
    int mojisuu = 0;

    long n = sc.nextLong();
    StringBuilder val = new StringBuilder();


    while(n>0){
      val.append(alpha((int)((n-1)%26)));
      n = (n-1) /26;
    }




      //0x61 = ９７ = a

      System.out.println(val.reverse());
    }








  static char alpha(int n){
      return (char)(n+97);
  }
} Main
import java.util.*;

public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);

    long pre_total = 0;
    long total = 0;
    int mojisuu = 0;

    long n = sc.nextLong();
    StringBuilder val = new StringBuilder();


    while(n>0){
      val.append(alpha((int)((n-1)%26)));
      n = (n-1) /26;
    }




      //0x61 = ９７ = a

      System.out.println(val.reverse());
    }








  static char alpha(int n){
      return (char)(n+97);
  }
}