import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        n--;
        List<Character> ansList = new ArrayList<>();
        while (n>=0) {
            long nAns = n % 26 + 97;
            ansList.add((char) nAns);
            n = n / 26 - 1;
        }

        for (int i=ansList.size()-1;i>=0;i--) {
            System.out.print(ansList.get(i));
        }
        System.out.println();
    }
} import java.util.ArrayList; ArrayList java.util import java.util.List; List java.util import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        n--;
        List<Character> ansList = new ArrayList<>();
        while (n>=0) {
            long nAns = n % 26 + 97;
            ansList.add((char) nAns);
            n = n / 26 - 1;
        }

        for (int i=ansList.size()-1;i>=0;i--) {
            System.out.print(ansList.get(i));
        }
        System.out.println();
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        n--;
        List<Character> ansList = new ArrayList<>();
        while (n>=0) {
            long nAns = n % 26 + 97;
            ansList.add((char) nAns);
            n = n / 26 - 1;
        }

        for (int i=ansList.size()-1;i>=0;i--) {
            System.out.print(ansList.get(i));
        }
        System.out.println();
    } main {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        n--;
        List<Character> ansList = new ArrayList<>();
        while (n>=0) {
            long nAns = n % 26 + 97;
            ansList.add((char) nAns);
            n = n / 26 - 1;
        }

        for (int i=ansList.size()-1;i>=0;i--) {
            System.out.print(ansList.get(i));
        }
        System.out.println();
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc n-- n List<Character> ansList = new ArrayList<>(); ansList new ArrayList<>() while (n>=0) {
            long nAns = n % 26 + 97;
            ansList.add((char) nAns);
            n = n / 26 - 1;
        } n>=0 n 0 {
            long nAns = n % 26 + 97;
            ansList.add((char) nAns);
            n = n / 26 - 1;
        } long nAns = n % 26 + 97; nAns n % 26 + 97 n % 26 n 26 97 ansList.add((char) nAns) ansList.add ansList (char) nAns n = n / 26 - 1 n n / 26 - 1 n / 26 n 26 1 for (int i=ansList.size()-1;i>=0;i--) {
            System.out.print(ansList.get(i));
        } int i=ansList.size()-1; int i=ansList.size()-1; i ansList.size()-1 ansList.size() ansList.size ansList 1 i>=0 i 0 i-- i-- i {
            System.out.print(ansList.get(i));
        } {
            System.out.print(ansList.get(i));
        } System.out.print(ansList.get(i)) System.out.print System.out System System.out ansList.get(i) ansList.get ansList i System.out.println() System.out.println System.out System System.out String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        n--;
        List<Character> ansList = new ArrayList<>();
        while (n>=0) {
            long nAns = n % 26 + 97;
            ansList.add((char) nAns);
            n = n / 26 - 1;
        }

        for (int i=ansList.size()-1;i>=0;i--) {
            System.out.print(ansList.get(i));
        }
        System.out.println();
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        n--;
        List<Character> ansList = new ArrayList<>();
        while (n>=0) {
            long nAns = n % 26 + 97;
            ansList.add((char) nAns);
            n = n / 26 - 1;
        }

        for (int i=ansList.size()-1;i>=0;i--) {
            System.out.print(ansList.get(i));
        }
        System.out.println();
    }
} Main
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        n--;
        List<Character> ansList = new ArrayList<>();
        while (n>=0) {
            long nAns = n % 26 + 97;
            ansList.add((char) nAns);
            n = n / 26 - 1;
        }

        for (int i=ansList.size()-1;i>=0;i--) {
            System.out.print(ansList.get(i));
        }
        System.out.println();
    }
}
