import java.util.*;
class Main {
	public static void main(String[] args) {
        String[] alphabet = {"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"};
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        ArrayList<Integer> list = new ArrayList<>();
        while(n>26){
            if(n%26==0){
                list.add(25);
                n=n/26-1;
            } else {
                list.add((int)(n%26-1));
                n/=26;
            }
        }
        System.out.print(alphabet[(int)n-1]);
        for(int i = list.size()-1;i>=0;i--){
            System.out.print(alphabet[list.get(i)]);
        }
    }
} import java.util.*; util.* java class Main {
	public static void main(String[] args) {
        String[] alphabet = {"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"};
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        ArrayList<Integer> list = new ArrayList<>();
        while(n>26){
            if(n%26==0){
                list.add(25);
                n=n/26-1;
            } else {
                list.add((int)(n%26-1));
                n/=26;
            }
        }
        System.out.print(alphabet[(int)n-1]);
        for(int i = list.size()-1;i>=0;i--){
            System.out.print(alphabet[list.get(i)]);
        }
    }
} Main public static void main(String[] args) {
        String[] alphabet = {"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"};
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        ArrayList<Integer> list = new ArrayList<>();
        while(n>26){
            if(n%26==0){
                list.add(25);
                n=n/26-1;
            } else {
                list.add((int)(n%26-1));
                n/=26;
            }
        }
        System.out.print(alphabet[(int)n-1]);
        for(int i = list.size()-1;i>=0;i--){
            System.out.print(alphabet[list.get(i)]);
        }
    } main {
        String[] alphabet = {"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"};
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        ArrayList<Integer> list = new ArrayList<>();
        while(n>26){
            if(n%26==0){
                list.add(25);
                n=n/26-1;
            } else {
                list.add((int)(n%26-1));
                n/=26;
            }
        }
        System.out.print(alphabet[(int)n-1]);
        for(int i = list.size()-1;i>=0;i--){
            System.out.print(alphabet[list.get(i)]);
        }
    } String[] alphabet = {"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"}; alphabet {"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" Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc ArrayList<Integer> list = new ArrayList<>(); list new ArrayList<>() while(n>26){
            if(n%26==0){
                list.add(25);
                n=n/26-1;
            } else {
                list.add((int)(n%26-1));
                n/=26;
            }
        } n>26 n 26 {
            if(n%26==0){
                list.add(25);
                n=n/26-1;
            } else {
                list.add((int)(n%26-1));
                n/=26;
            }
        } if(n%26==0){
                list.add(25);
                n=n/26-1;
            } else {
                list.add((int)(n%26-1));
                n/=26;
            } n%26==0 n%26 n 26 0 {
                list.add(25);
                n=n/26-1;
            } list.add(25) list.add list 25 n=n/26-1 n n/26-1 n/26 n 26 1 {
                list.add((int)(n%26-1));
                n/=26;
            } list.add((int)(n%26-1)) list.add list (int)(n%26-1) n%26 n 26 1 n/=26 n 26 System.out.print(alphabet[(int)n-1]) System.out.print System.out System System.out alphabet[(int)n-1] alphabet (int)n-1 (int)n 1 for(int i = list.size()-1;i>=0;i--){
            System.out.print(alphabet[list.get(i)]);
        } int i = list.size()-1; int i = list.size()-1; i list.size()-1 list.size() list.size list 1 i>=0 i 0 i-- i-- i {
            System.out.print(alphabet[list.get(i)]);
        } {
            System.out.print(alphabet[list.get(i)]);
        } System.out.print(alphabet[list.get(i)]) System.out.print System.out System System.out alphabet[list.get(i)] alphabet list.get(i) list.get list i String[] args args
import java.util.*;
class Main {
	public static void main(String[] args) {
        String[] alphabet = {"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"};
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        ArrayList<Integer> list = new ArrayList<>();
        while(n>26){
            if(n%26==0){
                list.add(25);
                n=n/26-1;
            } else {
                list.add((int)(n%26-1));
                n/=26;
            }
        }
        System.out.print(alphabet[(int)n-1]);
        for(int i = list.size()-1;i>=0;i--){
            System.out.print(alphabet[list.get(i)]);
        }
    }
}
