import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in);) {
			long n = sc.nextLong();

			StringBuilder sb = new StringBuilder();
			

			while (n > 26) {
				long amari = (n % 26) ;
				if(amari == 0) amari = 26;
				sb.insert(0, (char)(amari + 96));
				n = (n-1) / 26l;
			}
			
			long amari1 = n % 26;
			if(amari1 == 0) amari1 = 26;
			sb.insert(0, (char)(amari1 + 96));
			n = (n-1) / 26;

			System.out.println(sb.toString());

		} catch (Exception e) {
			e.printStackTrace();
		}

	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in);) {
			long n = sc.nextLong();

			StringBuilder sb = new StringBuilder();
			

			while (n > 26) {
				long amari = (n % 26) ;
				if(amari == 0) amari = 26;
				sb.insert(0, (char)(amari + 96));
				n = (n-1) / 26l;
			}
			
			long amari1 = n % 26;
			if(amari1 == 0) amari1 = 26;
			sb.insert(0, (char)(amari1 + 96));
			n = (n-1) / 26;

			System.out.println(sb.toString());

		} catch (Exception e) {
			e.printStackTrace();
		}

	}
} Main public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in);) {
			long n = sc.nextLong();

			StringBuilder sb = new StringBuilder();
			

			while (n > 26) {
				long amari = (n % 26) ;
				if(amari == 0) amari = 26;
				sb.insert(0, (char)(amari + 96));
				n = (n-1) / 26l;
			}
			
			long amari1 = n % 26;
			if(amari1 == 0) amari1 = 26;
			sb.insert(0, (char)(amari1 + 96));
			n = (n-1) / 26;

			System.out.println(sb.toString());

		} catch (Exception e) {
			e.printStackTrace();
		}

	} main {
		try (Scanner sc = new Scanner(System.in);) {
			long n = sc.nextLong();

			StringBuilder sb = new StringBuilder();
			

			while (n > 26) {
				long amari = (n % 26) ;
				if(amari == 0) amari = 26;
				sb.insert(0, (char)(amari + 96));
				n = (n-1) / 26l;
			}
			
			long amari1 = n % 26;
			if(amari1 == 0) amari1 = 26;
			sb.insert(0, (char)(amari1 + 96));
			n = (n-1) / 26;

			System.out.println(sb.toString());

		} catch (Exception e) {
			e.printStackTrace();
		}

	} try (Scanner sc = new Scanner(System.in);) {
			long n = sc.nextLong();

			StringBuilder sb = new StringBuilder();
			

			while (n > 26) {
				long amari = (n % 26) ;
				if(amari == 0) amari = 26;
				sb.insert(0, (char)(amari + 96));
				n = (n-1) / 26l;
			}
			
			long amari1 = n % 26;
			if(amari1 == 0) amari1 = 26;
			sb.insert(0, (char)(amari1 + 96));
			n = (n-1) / 26;

			System.out.println(sb.toString());

		} catch (Exception e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		} Exception e {
			e.printStackTrace();
		} e.printStackTrace() e.printStackTrace e {
			long n = sc.nextLong();

			StringBuilder sb = new StringBuilder();
			

			while (n > 26) {
				long amari = (n % 26) ;
				if(amari == 0) amari = 26;
				sb.insert(0, (char)(amari + 96));
				n = (n-1) / 26l;
			}
			
			long amari1 = n % 26;
			if(amari1 == 0) amari1 = 26;
			sb.insert(0, (char)(amari1 + 96));
			n = (n-1) / 26;

			System.out.println(sb.toString());

		} Scanner sc = new Scanner(System.in) Scanner sc = new Scanner(System.in) new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc StringBuilder sb = new StringBuilder(); sb new StringBuilder() while (n > 26) {
				long amari = (n % 26) ;
				if(amari == 0) amari = 26;
				sb.insert(0, (char)(amari + 96));
				n = (n-1) / 26l;
			} n > 26 n 26 {
				long amari = (n % 26) ;
				if(amari == 0) amari = 26;
				sb.insert(0, (char)(amari + 96));
				n = (n-1) / 26l;
			} long amari = (n % 26) ; amari (n % 26) n 26 if(amari == 0) amari = 26; amari == 0 amari 0 amari = 26 amari 26 sb.insert(0, (char)(amari + 96)) sb.insert sb 0 (char)(amari + 96) amari 96 n = (n-1) / 26l n (n-1) / 26l (n-1) n 1 26l long amari1 = n % 26; amari1 n % 26 n 26 if(amari1 == 0) amari1 = 26; amari1 == 0 amari1 0 amari1 = 26 amari1 26 sb.insert(0, (char)(amari1 + 96)) sb.insert sb 0 (char)(amari1 + 96) amari1 96 n = (n-1) / 26 n (n-1) / 26 (n-1) n 1 26 System.out.println(sb.toString()) System.out.println System.out System System.out sb.toString() sb.toString sb String[] args args public class Main {
	public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in);) {
			long n = sc.nextLong();

			StringBuilder sb = new StringBuilder();
			

			while (n > 26) {
				long amari = (n % 26) ;
				if(amari == 0) amari = 26;
				sb.insert(0, (char)(amari + 96));
				n = (n-1) / 26l;
			}
			
			long amari1 = n % 26;
			if(amari1 == 0) amari1 = 26;
			sb.insert(0, (char)(amari1 + 96));
			n = (n-1) / 26;

			System.out.println(sb.toString());

		} catch (Exception e) {
			e.printStackTrace();
		}

	}
} public class Main {
	public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in);) {
			long n = sc.nextLong();

			StringBuilder sb = new StringBuilder();
			

			while (n > 26) {
				long amari = (n % 26) ;
				if(amari == 0) amari = 26;
				sb.insert(0, (char)(amari + 96));
				n = (n-1) / 26l;
			}
			
			long amari1 = n % 26;
			if(amari1 == 0) amari1 = 26;
			sb.insert(0, (char)(amari1 + 96));
			n = (n-1) / 26;

			System.out.println(sb.toString());

		} catch (Exception e) {
			e.printStackTrace();
		}

	}
} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in);) {
			long n = sc.nextLong();

			StringBuilder sb = new StringBuilder();
			

			while (n > 26) {
				long amari = (n % 26) ;
				if(amari == 0) amari = 26;
				sb.insert(0, (char)(amari + 96));
				n = (n-1) / 26l;
			}
			
			long amari1 = n % 26;
			if(amari1 == 0) amari1 = 26;
			sb.insert(0, (char)(amari1 + 96));
			n = (n-1) / 26;

			System.out.println(sb.toString());

		} catch (Exception e) {
			e.printStackTrace();
		}

	}
}
