import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long input = scanner.nextLong();

        StringBuilder sbr = new StringBuilder();
        while ( input > 0 ){
            input -= 1;
            sbr.append( (char) ( 'a' + input % 26 ));
            input /= 26;
        }

        System.out.println( sbr.reverse().toString());
    }
} import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long input = scanner.nextLong();

        StringBuilder sbr = new StringBuilder();
        while ( input > 0 ){
            input -= 1;
            sbr.append( (char) ( 'a' + input % 26 ));
            input /= 26;
        }

        System.out.println( sbr.reverse().toString());
    }
} Main public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long input = scanner.nextLong();

        StringBuilder sbr = new StringBuilder();
        while ( input > 0 ){
            input -= 1;
            sbr.append( (char) ( 'a' + input % 26 ));
            input /= 26;
        }

        System.out.println( sbr.reverse().toString());
    } main {
        Scanner scanner = new Scanner(System.in);
        long input = scanner.nextLong();

        StringBuilder sbr = new StringBuilder();
        while ( input > 0 ){
            input -= 1;
            sbr.append( (char) ( 'a' + input % 26 ));
            input /= 26;
        }

        System.out.println( sbr.reverse().toString());
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) long input = scanner.nextLong(); input scanner.nextLong() scanner.nextLong scanner StringBuilder sbr = new StringBuilder(); sbr new StringBuilder() while ( input > 0 ){
            input -= 1;
            sbr.append( (char) ( 'a' + input % 26 ));
            input /= 26;
        } input > 0 input 0 {
            input -= 1;
            sbr.append( (char) ( 'a' + input % 26 ));
            input /= 26;
        } input -= 1 input 1 sbr.append( (char) ( 'a' + input % 26 )) sbr.append sbr (char) ( 'a' + input % 26 ) 'a' input % 26 input 26 input /= 26 input 26 System.out.println( sbr.reverse().toString()) System.out.println System.out System System.out sbr.reverse().toString() sbr.reverse().toString sbr.reverse() sbr.reverse sbr String[] args args public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long input = scanner.nextLong();

        StringBuilder sbr = new StringBuilder();
        while ( input > 0 ){
            input -= 1;
            sbr.append( (char) ( 'a' + input % 26 ));
            input /= 26;
        }

        System.out.println( sbr.reverse().toString());
    }
} public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long input = scanner.nextLong();

        StringBuilder sbr = new StringBuilder();
        while ( input > 0 ){
            input -= 1;
            sbr.append( (char) ( 'a' + input % 26 ));
            input /= 26;
        }

        System.out.println( sbr.reverse().toString());
    }
} Main
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long input = scanner.nextLong();

        StringBuilder sbr = new StringBuilder();
        while ( input > 0 ){
            input -= 1;
            sbr.append( (char) ( 'a' + input % 26 ));
            input /= 26;
        }

        System.out.println( sbr.reverse().toString());
    }
}