import java.util.Scanner;

class Main {
    static int serialNum;
    static String[] charList = {"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"};
    static String output ="";
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        sc.close();
        convertChar(n);
        System.out.println(output);

    }

    static long convertChar(long num){
        if(num==0){
            return 0;
        }
        output = charList[(int) ((num-1)%26)] + output;
        return convertChar((num-1)/26);
    }
} import java.util.Scanner; Scanner java.util class Main {
    static int serialNum;
    static String[] charList = {"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"};
    static String output ="";
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        sc.close();
        convertChar(n);
        System.out.println(output);

    }

    static long convertChar(long num){
        if(num==0){
            return 0;
        }
        output = charList[(int) ((num-1)%26)] + output;
        return convertChar((num-1)/26);
    }
} Main static int serialNum; serialNum static String[] charList = {"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"}; charList {"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" "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" static String output =""; output "" public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        sc.close();
        convertChar(n);
        System.out.println(output);

    } main {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        sc.close();
        convertChar(n);
        System.out.println(output);

    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc sc.close() sc.close sc convertChar(n) convertChar n System.out.println(output) System.out.println System.out System System.out output String args[] args static long convertChar(long num){
        if(num==0){
            return 0;
        }
        output = charList[(int) ((num-1)%26)] + output;
        return convertChar((num-1)/26);
    } convertChar {
        if(num==0){
            return 0;
        }
        output = charList[(int) ((num-1)%26)] + output;
        return convertChar((num-1)/26);
    } if(num==0){
            return 0;
        } num==0 num 0 {
            return 0;
        } return 0; 0 output = charList[(int) ((num-1)%26)] + output output charList[(int) ((num-1)%26)] + output charList[(int) ((num-1)%26)] charList (int) ((num-1)%26) (num-1) num 1 26 output return convertChar((num-1)/26); convertChar((num-1)/26) convertChar (num-1)/26 (num-1) num 1 26 long num num
import java.util.Scanner;

class Main {
    static int serialNum;
    static String[] charList = {"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"};
    static String output ="";
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        sc.close();
        convertChar(n);
        System.out.println(output);

    }

    static long convertChar(long num){
        if(num==0){
            return 0;
        }
        output = charList[(int) ((num-1)%26)] + output;
        return convertChar((num-1)/26);
    }
}