import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        long n = s.nextLong();
        String a = "";
        long counter = 0;
        while(n>0){
            counter= (n-1)%26;
            char a1 = (char)('a'+counter);
            a=a1+a;
            n = (n-1)/26;
        }
        System.out.println(a);
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        long n = s.nextLong();
        String a = "";
        long counter = 0;
        while(n>0){
            counter= (n-1)%26;
            char a1 = (char)('a'+counter);
            a=a1+a;
            n = (n-1)/26;
        }
        System.out.println(a);
    }
} Main public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        long n = s.nextLong();
        String a = "";
        long counter = 0;
        while(n>0){
            counter= (n-1)%26;
            char a1 = (char)('a'+counter);
            a=a1+a;
            n = (n-1)/26;
        }
        System.out.println(a);
    } main {
        Scanner s = new Scanner(System.in);
        long n = s.nextLong();
        String a = "";
        long counter = 0;
        while(n>0){
            counter= (n-1)%26;
            char a1 = (char)('a'+counter);
            a=a1+a;
            n = (n-1)/26;
        }
        System.out.println(a);
    } Scanner s = new Scanner(System.in); s new Scanner(System.in) long n = s.nextLong(); n s.nextLong() s.nextLong s String a = ""; a "" long counter = 0; counter 0 while(n>0){
            counter= (n-1)%26;
            char a1 = (char)('a'+counter);
            a=a1+a;
            n = (n-1)/26;
        } n>0 n 0 {
            counter= (n-1)%26;
            char a1 = (char)('a'+counter);
            a=a1+a;
            n = (n-1)/26;
        } counter= (n-1)%26 counter (n-1)%26 (n-1) n 1 26 char a1 = (char)('a'+counter); a1 (char)('a'+counter) 'a' counter a=a1+a a a1+a a1 a n = (n-1)/26 n (n-1)/26 (n-1) n 1 26 System.out.println(a) System.out.println System.out System System.out a String[] args args public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        long n = s.nextLong();
        String a = "";
        long counter = 0;
        while(n>0){
            counter= (n-1)%26;
            char a1 = (char)('a'+counter);
            a=a1+a;
            n = (n-1)/26;
        }
        System.out.println(a);
    }
} public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        long n = s.nextLong();
        String a = "";
        long counter = 0;
        while(n>0){
            counter= (n-1)%26;
            char a1 = (char)('a'+counter);
            a=a1+a;
            n = (n-1)/26;
        }
        System.out.println(a);
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        long n = s.nextLong();
        String a = "";
        long counter = 0;
        while(n>0){
            counter= (n-1)%26;
            char a1 = (char)('a'+counter);
            a=a1+a;
            n = (n-1)/26;
        }
        System.out.println(a);
    }
}
