import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        String ans = "";
        while (true) {
            long c = n % 26;
            if (c == 0) {
                c = 26;
            }
            ans = String.valueOf((char)(0x60 + c)) + ans;
            if (n <= 26) {
                break;
            }
            n--;
            n /= 26;
        }
        System.out.println(ans);
    }
} 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();
        String ans = "";
        while (true) {
            long c = n % 26;
            if (c == 0) {
                c = 26;
            }
            ans = String.valueOf((char)(0x60 + c)) + ans;
            if (n <= 26) {
                break;
            }
            n--;
            n /= 26;
        }
        System.out.println(ans);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        String ans = "";
        while (true) {
            long c = n % 26;
            if (c == 0) {
                c = 26;
            }
            ans = String.valueOf((char)(0x60 + c)) + ans;
            if (n <= 26) {
                break;
            }
            n--;
            n /= 26;
        }
        System.out.println(ans);
    } main {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        String ans = "";
        while (true) {
            long c = n % 26;
            if (c == 0) {
                c = 26;
            }
            ans = String.valueOf((char)(0x60 + c)) + ans;
            if (n <= 26) {
                break;
            }
            n--;
            n /= 26;
        }
        System.out.println(ans);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc String ans = ""; ans "" while (true) {
            long c = n % 26;
            if (c == 0) {
                c = 26;
            }
            ans = String.valueOf((char)(0x60 + c)) + ans;
            if (n <= 26) {
                break;
            }
            n--;
            n /= 26;
        } true {
            long c = n % 26;
            if (c == 0) {
                c = 26;
            }
            ans = String.valueOf((char)(0x60 + c)) + ans;
            if (n <= 26) {
                break;
            }
            n--;
            n /= 26;
        } long c = n % 26; c n % 26 n 26 if (c == 0) {
                c = 26;
            } c == 0 c 0 {
                c = 26;
            } c = 26 c 26 ans = String.valueOf((char)(0x60 + c)) + ans ans String.valueOf((char)(0x60 + c)) + ans String.valueOf((char)(0x60 + c)) String.valueOf String (char)(0x60 + c) 0x60 c ans if (n <= 26) {
                break;
            } n <= 26 n 26 {
                break;
            } break; n-- n n /= 26 n 26 System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        String ans = "";
        while (true) {
            long c = n % 26;
            if (c == 0) {
                c = 26;
            }
            ans = String.valueOf((char)(0x60 + c)) + ans;
            if (n <= 26) {
                break;
            }
            n--;
            n /= 26;
        }
        System.out.println(ans);
    }
} public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        String ans = "";
        while (true) {
            long c = n % 26;
            if (c == 0) {
                c = 26;
            }
            ans = String.valueOf((char)(0x60 + c)) + ans;
            if (n <= 26) {
                break;
            }
            n--;
            n /= 26;
        }
        System.out.println(ans);
    }
} Main
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        String ans = "";
        while (true) {
            long c = n % 26;
            if (c == 0) {
                c = 26;
            }
            ans = String.valueOf((char)(0x60 + c)) + ans;
            if (n <= 26) {
                break;
            }
            n--;
            n /= 26;
        }
        System.out.println(ans);
    }
}
