import java.util.Scanner;

class Main {

    static char[] alphabet = "abcdefghijklmnopqrstuvwxyz".toCharArray();

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        long n = sc.nextLong();

        long tmp = n;
        int keta = 1;
        while (true) {
            tmp -= Math.pow(26, keta);
            if (tmp <= 0) {
                break;
            }
            keta++;
        }

        String name = "";
        for (; keta > 0; keta--) {
            int idx = (int)((n - 1) % 26);
            name = alphabet[idx] + name;
            n = (n - 1) / 26;
        }

        System.out.println(name);
    }
} import java.util.Scanner; Scanner java.util class Main {

    static char[] alphabet = "abcdefghijklmnopqrstuvwxyz".toCharArray();

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        long n = sc.nextLong();

        long tmp = n;
        int keta = 1;
        while (true) {
            tmp -= Math.pow(26, keta);
            if (tmp <= 0) {
                break;
            }
            keta++;
        }

        String name = "";
        for (; keta > 0; keta--) {
            int idx = (int)((n - 1) % 26);
            name = alphabet[idx] + name;
            n = (n - 1) / 26;
        }

        System.out.println(name);
    }
} Main static char[] alphabet = "abcdefghijklmnopqrstuvwxyz".toCharArray(); alphabet "abcdefghijklmnopqrstuvwxyz".toCharArray() "abcdefghijklmnopqrstuvwxyz".toCharArray "abcdefghijklmnopqrstuvwxyz" public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        long n = sc.nextLong();

        long tmp = n;
        int keta = 1;
        while (true) {
            tmp -= Math.pow(26, keta);
            if (tmp <= 0) {
                break;
            }
            keta++;
        }

        String name = "";
        for (; keta > 0; keta--) {
            int idx = (int)((n - 1) % 26);
            name = alphabet[idx] + name;
            n = (n - 1) / 26;
        }

        System.out.println(name);
    } main {
        Scanner sc = new Scanner(System.in);

        long n = sc.nextLong();

        long tmp = n;
        int keta = 1;
        while (true) {
            tmp -= Math.pow(26, keta);
            if (tmp <= 0) {
                break;
            }
            keta++;
        }

        String name = "";
        for (; keta > 0; keta--) {
            int idx = (int)((n - 1) % 26);
            name = alphabet[idx] + name;
            n = (n - 1) / 26;
        }

        System.out.println(name);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc long tmp = n; tmp n int keta = 1; keta 1 while (true) {
            tmp -= Math.pow(26, keta);
            if (tmp <= 0) {
                break;
            }
            keta++;
        } true {
            tmp -= Math.pow(26, keta);
            if (tmp <= 0) {
                break;
            }
            keta++;
        } tmp -= Math.pow(26, keta) tmp Math.pow(26, keta) Math.pow Math 26 keta if (tmp <= 0) {
                break;
            } tmp <= 0 tmp 0 {
                break;
            } break; keta++ keta String name = ""; name "" for (; keta > 0; keta--) {
            int idx = (int)((n - 1) % 26);
            name = alphabet[idx] + name;
            n = (n - 1) / 26;
        } ; keta > 0 keta 0 keta-- keta-- keta {
            int idx = (int)((n - 1) % 26);
            name = alphabet[idx] + name;
            n = (n - 1) / 26;
        } {
            int idx = (int)((n - 1) % 26);
            name = alphabet[idx] + name;
            n = (n - 1) / 26;
        } int idx = (int)((n - 1) % 26); idx (int)((n - 1) % 26) (n - 1) n 1 26 name = alphabet[idx] + name name alphabet[idx] + name alphabet[idx] alphabet idx name n = (n - 1) / 26 n (n - 1) / 26 (n - 1) n 1 26 System.out.println(name) System.out.println System.out System System.out name String[] args args
import java.util.Scanner;

class Main {

    static char[] alphabet = "abcdefghijklmnopqrstuvwxyz".toCharArray();

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        long n = sc.nextLong();

        long tmp = n;
        int keta = 1;
        while (true) {
            tmp -= Math.pow(26, keta);
            if (tmp <= 0) {
                break;
            }
            keta++;
        }

        String name = "";
        for (; keta > 0; keta--) {
            int idx = (int)((n - 1) % 26);
            name = alphabet[idx] + name;
            n = (n - 1) / 26;
        }

        System.out.println(name);
    }
}
