import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        StringBuilder sb = new StringBuilder();
        while (n>0) {
            n -=1;
            long amari = n % 26;
            sb.append((char)(amari + 'a'));
            n /= 26;
        }
        System.out.println(sb.reverse().toString());
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        StringBuilder sb = new StringBuilder();
        while (n>0) {
            n -=1;
            long amari = n % 26;
            sb.append((char)(amari + 'a'));
            n /= 26;
        }
        System.out.println(sb.reverse().toString());
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        StringBuilder sb = new StringBuilder();
        while (n>0) {
            n -=1;
            long amari = n % 26;
            sb.append((char)(amari + 'a'));
            n /= 26;
        }
        System.out.println(sb.reverse().toString());
    } main {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        StringBuilder sb = new StringBuilder();
        while (n>0) {
            n -=1;
            long amari = n % 26;
            sb.append((char)(amari + 'a'));
            n /= 26;
        }
        System.out.println(sb.reverse().toString());
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc StringBuilder sb = new StringBuilder(); sb new StringBuilder() while (n>0) {
            n -=1;
            long amari = n % 26;
            sb.append((char)(amari + 'a'));
            n /= 26;
        } n>0 n 0 {
            n -=1;
            long amari = n % 26;
            sb.append((char)(amari + 'a'));
            n /= 26;
        } n -=1 n 1 long amari = n % 26; amari n % 26 n 26 sb.append((char)(amari + 'a')) sb.append sb (char)(amari + 'a') amari 'a' n /= 26 n 26 System.out.println(sb.reverse().toString()) System.out.println System.out System System.out sb.reverse().toString() sb.reverse().toString sb.reverse() sb.reverse sb String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        StringBuilder sb = new StringBuilder();
        while (n>0) {
            n -=1;
            long amari = n % 26;
            sb.append((char)(amari + 'a'));
            n /= 26;
        }
        System.out.println(sb.reverse().toString());
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        StringBuilder sb = new StringBuilder();
        while (n>0) {
            n -=1;
            long amari = n % 26;
            sb.append((char)(amari + 'a'));
            n /= 26;
        }
        System.out.println(sb.reverse().toString());
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        StringBuilder sb = new StringBuilder();
        while (n>0) {
            n -=1;
            long amari = n % 26;
            sb.append((char)(amari + 'a'));
            n /= 26;
        }
        System.out.println(sb.reverse().toString());
    }
}