import java.util.*;

public class Main {
    public static void main(final String[] args) {
        final Scanner sc = new Scanner(System.in);
        // 整数の入力
        // final int a = sc.nextInt();
        // 文字列の入力
        // final String s1 = sc.next();
        long resN = Long.parseLong(sc.next());
        long modN = 0;

        sc.close();
        StringBuilder sb = new StringBuilder();

        while (resN > 0) {
            modN = resN % 26;
            if (modN == 0) {
                modN = 26;
            }
            resN = (resN - modN) / 26;

            sb.insert(0, (char) (96 + modN));
        }
        System.out.println(sb.toString());
    }
} import java.util.*; util.* java public class Main {
    public static void main(final String[] args) {
        final Scanner sc = new Scanner(System.in);
        // 整数の入力
        // final int a = sc.nextInt();
        // 文字列の入力
        // final String s1 = sc.next();
        long resN = Long.parseLong(sc.next());
        long modN = 0;

        sc.close();
        StringBuilder sb = new StringBuilder();

        while (resN > 0) {
            modN = resN % 26;
            if (modN == 0) {
                modN = 26;
            }
            resN = (resN - modN) / 26;

            sb.insert(0, (char) (96 + modN));
        }
        System.out.println(sb.toString());
    }
} Main public static void main(final String[] args) {
        final Scanner sc = new Scanner(System.in);
        // 整数の入力
        // final int a = sc.nextInt();
        // 文字列の入力
        // final String s1 = sc.next();
        long resN = Long.parseLong(sc.next());
        long modN = 0;

        sc.close();
        StringBuilder sb = new StringBuilder();

        while (resN > 0) {
            modN = resN % 26;
            if (modN == 0) {
                modN = 26;
            }
            resN = (resN - modN) / 26;

            sb.insert(0, (char) (96 + modN));
        }
        System.out.println(sb.toString());
    } main {
        final Scanner sc = new Scanner(System.in);
        // 整数の入力
        // final int a = sc.nextInt();
        // 文字列の入力
        // final String s1 = sc.next();
        long resN = Long.parseLong(sc.next());
        long modN = 0;

        sc.close();
        StringBuilder sb = new StringBuilder();

        while (resN > 0) {
            modN = resN % 26;
            if (modN == 0) {
                modN = 26;
            }
            resN = (resN - modN) / 26;

            sb.insert(0, (char) (96 + modN));
        }
        System.out.println(sb.toString());
    } final Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long resN = Long.parseLong(sc.next()); resN Long.parseLong(sc.next()) Long.parseLong Long sc.next() sc.next sc long modN = 0; modN 0 sc.close() sc.close sc StringBuilder sb = new StringBuilder(); sb new StringBuilder() while (resN > 0) {
            modN = resN % 26;
            if (modN == 0) {
                modN = 26;
            }
            resN = (resN - modN) / 26;

            sb.insert(0, (char) (96 + modN));
        } resN > 0 resN 0 {
            modN = resN % 26;
            if (modN == 0) {
                modN = 26;
            }
            resN = (resN - modN) / 26;

            sb.insert(0, (char) (96 + modN));
        } modN = resN % 26 modN resN % 26 resN 26 if (modN == 0) {
                modN = 26;
            } modN == 0 modN 0 {
                modN = 26;
            } modN = 26 modN 26 resN = (resN - modN) / 26 resN (resN - modN) / 26 (resN - modN) resN modN 26 sb.insert(0, (char) (96 + modN)) sb.insert sb 0 (char) (96 + modN) 96 modN System.out.println(sb.toString()) System.out.println System.out System System.out sb.toString() sb.toString sb final String[] args args public class Main {
    public static void main(final String[] args) {
        final Scanner sc = new Scanner(System.in);
        // 整数の入力
        // final int a = sc.nextInt();
        // 文字列の入力
        // final String s1 = sc.next();
        long resN = Long.parseLong(sc.next());
        long modN = 0;

        sc.close();
        StringBuilder sb = new StringBuilder();

        while (resN > 0) {
            modN = resN % 26;
            if (modN == 0) {
                modN = 26;
            }
            resN = (resN - modN) / 26;

            sb.insert(0, (char) (96 + modN));
        }
        System.out.println(sb.toString());
    }
} public class Main {
    public static void main(final String[] args) {
        final Scanner sc = new Scanner(System.in);
        // 整数の入力
        // final int a = sc.nextInt();
        // 文字列の入力
        // final String s1 = sc.next();
        long resN = Long.parseLong(sc.next());
        long modN = 0;

        sc.close();
        StringBuilder sb = new StringBuilder();

        while (resN > 0) {
            modN = resN % 26;
            if (modN == 0) {
                modN = 26;
            }
            resN = (resN - modN) / 26;

            sb.insert(0, (char) (96 + modN));
        }
        System.out.println(sb.toString());
    }
} Main
import java.util.*;

public class Main {
    public static void main(final String[] args) {
        final Scanner sc = new Scanner(System.in);
        // 整数の入力
        // final int a = sc.nextInt();
        // 文字列の入力
        // final String s1 = sc.next();
        long resN = Long.parseLong(sc.next());
        long modN = 0;

        sc.close();
        StringBuilder sb = new StringBuilder();

        while (resN > 0) {
            modN = resN % 26;
            if (modN == 0) {
                modN = 26;
            }
            resN = (resN - modN) / 26;

            sb.insert(0, (char) (96 + modN));
        }
        System.out.println(sb.toString());
    }
}