import java.math.BigInteger;
import java.nio.Buffer;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;
import java.util.Vector;

public class Main {
    public static Scanner r=new Scanner(System.in);
    public static void main(String[] args) {
        long n;
        n=r.nextLong();
        --n;
        ArrayList<Integer> a=new ArrayList<>();
        while(n>-1){
            int ch=(int)(n%26);
            a.add(ch);
            n/=26;
            --n;
        }
        Collections.reverse(a);
        for(int x:a){
            System.out.print((char)(x+'a'));
        }
    }
} import java.math.BigInteger; BigInteger java.math import java.nio.Buffer; Buffer java.nio import java.util.ArrayList; ArrayList java.util import java.util.Collections; Collections java.util import java.util.Scanner; Scanner java.util import java.util.Vector; Vector java.util public class Main {
    public static Scanner r=new Scanner(System.in);
    public static void main(String[] args) {
        long n;
        n=r.nextLong();
        --n;
        ArrayList<Integer> a=new ArrayList<>();
        while(n>-1){
            int ch=(int)(n%26);
            a.add(ch);
            n/=26;
            --n;
        }
        Collections.reverse(a);
        for(int x:a){
            System.out.print((char)(x+'a'));
        }
    }
} Main public static Scanner r=new Scanner(System.in); r new Scanner(System.in) public static void main(String[] args) {
        long n;
        n=r.nextLong();
        --n;
        ArrayList<Integer> a=new ArrayList<>();
        while(n>-1){
            int ch=(int)(n%26);
            a.add(ch);
            n/=26;
            --n;
        }
        Collections.reverse(a);
        for(int x:a){
            System.out.print((char)(x+'a'));
        }
    } main {
        long n;
        n=r.nextLong();
        --n;
        ArrayList<Integer> a=new ArrayList<>();
        while(n>-1){
            int ch=(int)(n%26);
            a.add(ch);
            n/=26;
            --n;
        }
        Collections.reverse(a);
        for(int x:a){
            System.out.print((char)(x+'a'));
        }
    } long n; n n=r.nextLong() n r.nextLong() r.nextLong r --n n ArrayList<Integer> a=new ArrayList<>(); a new ArrayList<>() while(n>-1){
            int ch=(int)(n%26);
            a.add(ch);
            n/=26;
            --n;
        } n>-1 n -1 1 {
            int ch=(int)(n%26);
            a.add(ch);
            n/=26;
            --n;
        } int ch=(int)(n%26); ch (int)(n%26) n 26 a.add(ch) a.add a ch n/=26 n 26 --n n Collections.reverse(a) Collections.reverse Collections a for(int x:a){
            System.out.print((char)(x+'a'));
        } int x a {
            System.out.print((char)(x+'a'));
        } {
            System.out.print((char)(x+'a'));
        } System.out.print((char)(x+'a')) System.out.print System.out System System.out (char)(x+'a') x 'a' String[] args args public class Main {
    public static Scanner r=new Scanner(System.in);
    public static void main(String[] args) {
        long n;
        n=r.nextLong();
        --n;
        ArrayList<Integer> a=new ArrayList<>();
        while(n>-1){
            int ch=(int)(n%26);
            a.add(ch);
            n/=26;
            --n;
        }
        Collections.reverse(a);
        for(int x:a){
            System.out.print((char)(x+'a'));
        }
    }
} public class Main {
    public static Scanner r=new Scanner(System.in);
    public static void main(String[] args) {
        long n;
        n=r.nextLong();
        --n;
        ArrayList<Integer> a=new ArrayList<>();
        while(n>-1){
            int ch=(int)(n%26);
            a.add(ch);
            n/=26;
            --n;
        }
        Collections.reverse(a);
        for(int x:a){
            System.out.print((char)(x+'a'));
        }
    }
} Main
import java.math.BigInteger;
import java.nio.Buffer;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;
import java.util.Vector;

public class Main {
    public static Scanner r=new Scanner(System.in);
    public static void main(String[] args) {
        long n;
        n=r.nextLong();
        --n;
        ArrayList<Integer> a=new ArrayList<>();
        while(n>-1){
            int ch=(int)(n%26);
            a.add(ch);
            n/=26;
            --n;
        }
        Collections.reverse(a);
        for(int x:a){
            System.out.print((char)(x+'a'));
        }
    }
}
