import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		long n = scan.nextLong();
		String[] list = {"a","b","c","d","e","f","g","h","i","j",
						"k","l","m","n","o","p","q","r","s","t",
						"u","v","w","x","y","z"};
		int exp = 0;
		String name = "";
		
		long pow = 0;
		for(int i=1;i<=12;i++) {
			if(pow < n) {
				pow = (long) (pow + Math.pow(26, i));
			}else {
				exp = i-1;
				break;
			}
		}
		
		long s = 0;
		String[] namelist = new String[exp];
		for(int j=0;j<exp;j++) {
			if(n > 26) {
				s = n % 26;
				n = n / 26;
				if(s == 0) {
					s = 26;
					n = n - 1;
				}
				namelist[j] = list[(int) (s-1)];
			}else {
				namelist[j] = list[(int) (n-1)];
			}
		}
		for(int k=exp-1;k>=0;k--) {
			name = name + namelist[k];
		}
		System.out.println(name);
	}

} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		long n = scan.nextLong();
		String[] list = {"a","b","c","d","e","f","g","h","i","j",
						"k","l","m","n","o","p","q","r","s","t",
						"u","v","w","x","y","z"};
		int exp = 0;
		String name = "";
		
		long pow = 0;
		for(int i=1;i<=12;i++) {
			if(pow < n) {
				pow = (long) (pow + Math.pow(26, i));
			}else {
				exp = i-1;
				break;
			}
		}
		
		long s = 0;
		String[] namelist = new String[exp];
		for(int j=0;j<exp;j++) {
			if(n > 26) {
				s = n % 26;
				n = n / 26;
				if(s == 0) {
					s = 26;
					n = n - 1;
				}
				namelist[j] = list[(int) (s-1)];
			}else {
				namelist[j] = list[(int) (n-1)];
			}
		}
		for(int k=exp-1;k>=0;k--) {
			name = name + namelist[k];
		}
		System.out.println(name);
	}

} Main public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		long n = scan.nextLong();
		String[] list = {"a","b","c","d","e","f","g","h","i","j",
						"k","l","m","n","o","p","q","r","s","t",
						"u","v","w","x","y","z"};
		int exp = 0;
		String name = "";
		
		long pow = 0;
		for(int i=1;i<=12;i++) {
			if(pow < n) {
				pow = (long) (pow + Math.pow(26, i));
			}else {
				exp = i-1;
				break;
			}
		}
		
		long s = 0;
		String[] namelist = new String[exp];
		for(int j=0;j<exp;j++) {
			if(n > 26) {
				s = n % 26;
				n = n / 26;
				if(s == 0) {
					s = 26;
					n = n - 1;
				}
				namelist[j] = list[(int) (s-1)];
			}else {
				namelist[j] = list[(int) (n-1)];
			}
		}
		for(int k=exp-1;k>=0;k--) {
			name = name + namelist[k];
		}
		System.out.println(name);
	} main {
		Scanner scan = new Scanner(System.in);
		long n = scan.nextLong();
		String[] list = {"a","b","c","d","e","f","g","h","i","j",
						"k","l","m","n","o","p","q","r","s","t",
						"u","v","w","x","y","z"};
		int exp = 0;
		String name = "";
		
		long pow = 0;
		for(int i=1;i<=12;i++) {
			if(pow < n) {
				pow = (long) (pow + Math.pow(26, i));
			}else {
				exp = i-1;
				break;
			}
		}
		
		long s = 0;
		String[] namelist = new String[exp];
		for(int j=0;j<exp;j++) {
			if(n > 26) {
				s = n % 26;
				n = n / 26;
				if(s == 0) {
					s = 26;
					n = n - 1;
				}
				namelist[j] = list[(int) (s-1)];
			}else {
				namelist[j] = list[(int) (n-1)];
			}
		}
		for(int k=exp-1;k>=0;k--) {
			name = name + namelist[k];
		}
		System.out.println(name);
	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) long n = scan.nextLong(); n scan.nextLong() scan.nextLong scan String[] list = {"a","b","c","d","e","f","g","h","i","j",
						"k","l","m","n","o","p","q","r","s","t",
						"u","v","w","x","y","z"}; list {"a","b","c","d","e","f","g","h","i","j",
						"k","l","m","n","o","p","q","r","s","t",
						"u","v","w","x","y","z"} "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s" "t" "u" "v" "w" "x" "y" "z" int exp = 0; exp 0 String name = ""; name "" long pow = 0; pow 0 for(int i=1;i<=12;i++) {
			if(pow < n) {
				pow = (long) (pow + Math.pow(26, i));
			}else {
				exp = i-1;
				break;
			}
		} int i=1; int i=1; i 1 i<=12 i 12 i++ i++ i {
			if(pow < n) {
				pow = (long) (pow + Math.pow(26, i));
			}else {
				exp = i-1;
				break;
			}
		} {
			if(pow < n) {
				pow = (long) (pow + Math.pow(26, i));
			}else {
				exp = i-1;
				break;
			}
		} if(pow < n) {
				pow = (long) (pow + Math.pow(26, i));
			}else {
				exp = i-1;
				break;
			} pow < n pow n {
				pow = (long) (pow + Math.pow(26, i));
			} pow = (long) (pow + Math.pow(26, i)) pow (long) (pow + Math.pow(26, i)) pow Math.pow(26, i) Math.pow Math 26 i {
				exp = i-1;
				break;
			} exp = i-1 exp i-1 i 1 break; long s = 0; s 0 String[] namelist = new String[exp]; namelist new String[exp] exp for(int j=0;j<exp;j++) {
			if(n > 26) {
				s = n % 26;
				n = n / 26;
				if(s == 0) {
					s = 26;
					n = n - 1;
				}
				namelist[j] = list[(int) (s-1)];
			}else {
				namelist[j] = list[(int) (n-1)];
			}
		} int j=0; int j=0; j 0 j<exp j exp j++ j++ j {
			if(n > 26) {
				s = n % 26;
				n = n / 26;
				if(s == 0) {
					s = 26;
					n = n - 1;
				}
				namelist[j] = list[(int) (s-1)];
			}else {
				namelist[j] = list[(int) (n-1)];
			}
		} {
			if(n > 26) {
				s = n % 26;
				n = n / 26;
				if(s == 0) {
					s = 26;
					n = n - 1;
				}
				namelist[j] = list[(int) (s-1)];
			}else {
				namelist[j] = list[(int) (n-1)];
			}
		} if(n > 26) {
				s = n % 26;
				n = n / 26;
				if(s == 0) {
					s = 26;
					n = n - 1;
				}
				namelist[j] = list[(int) (s-1)];
			}else {
				namelist[j] = list[(int) (n-1)];
			} n > 26 n 26 {
				s = n % 26;
				n = n / 26;
				if(s == 0) {
					s = 26;
					n = n - 1;
				}
				namelist[j] = list[(int) (s-1)];
			} s = n % 26 s n % 26 n 26 n = n / 26 n n / 26 n 26 if(s == 0) {
					s = 26;
					n = n - 1;
				} s == 0 s 0 {
					s = 26;
					n = n - 1;
				} s = 26 s 26 n = n - 1 n n - 1 n 1 namelist[j] = list[(int) (s-1)] namelist[j] namelist j list[(int) (s-1)] list (int) (s-1) s 1 {
				namelist[j] = list[(int) (n-1)];
			} namelist[j] = list[(int) (n-1)] namelist[j] namelist j list[(int) (n-1)] list (int) (n-1) n 1 for(int k=exp-1;k>=0;k--) {
			name = name + namelist[k];
		} int k=exp-1; int k=exp-1; k exp-1 exp 1 k>=0 k 0 k-- k-- k {
			name = name + namelist[k];
		} {
			name = name + namelist[k];
		} name = name + namelist[k] name name + namelist[k] name namelist[k] namelist k System.out.println(name) System.out.println System.out System System.out name String[] args args public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		long n = scan.nextLong();
		String[] list = {"a","b","c","d","e","f","g","h","i","j",
						"k","l","m","n","o","p","q","r","s","t",
						"u","v","w","x","y","z"};
		int exp = 0;
		String name = "";
		
		long pow = 0;
		for(int i=1;i<=12;i++) {
			if(pow < n) {
				pow = (long) (pow + Math.pow(26, i));
			}else {
				exp = i-1;
				break;
			}
		}
		
		long s = 0;
		String[] namelist = new String[exp];
		for(int j=0;j<exp;j++) {
			if(n > 26) {
				s = n % 26;
				n = n / 26;
				if(s == 0) {
					s = 26;
					n = n - 1;
				}
				namelist[j] = list[(int) (s-1)];
			}else {
				namelist[j] = list[(int) (n-1)];
			}
		}
		for(int k=exp-1;k>=0;k--) {
			name = name + namelist[k];
		}
		System.out.println(name);
	}

} public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		long n = scan.nextLong();
		String[] list = {"a","b","c","d","e","f","g","h","i","j",
						"k","l","m","n","o","p","q","r","s","t",
						"u","v","w","x","y","z"};
		int exp = 0;
		String name = "";
		
		long pow = 0;
		for(int i=1;i<=12;i++) {
			if(pow < n) {
				pow = (long) (pow + Math.pow(26, i));
			}else {
				exp = i-1;
				break;
			}
		}
		
		long s = 0;
		String[] namelist = new String[exp];
		for(int j=0;j<exp;j++) {
			if(n > 26) {
				s = n % 26;
				n = n / 26;
				if(s == 0) {
					s = 26;
					n = n - 1;
				}
				namelist[j] = list[(int) (s-1)];
			}else {
				namelist[j] = list[(int) (n-1)];
			}
		}
		for(int k=exp-1;k>=0;k--) {
			name = name + namelist[k];
		}
		System.out.println(name);
	}

} Main
import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		long n = scan.nextLong();
		String[] list = {"a","b","c","d","e","f","g","h","i","j",
						"k","l","m","n","o","p","q","r","s","t",
						"u","v","w","x","y","z"};
		int exp = 0;
		String name = "";
		
		long pow = 0;
		for(int i=1;i<=12;i++) {
			if(pow < n) {
				pow = (long) (pow + Math.pow(26, i));
			}else {
				exp = i-1;
				break;
			}
		}
		
		long s = 0;
		String[] namelist = new String[exp];
		for(int j=0;j<exp;j++) {
			if(n > 26) {
				s = n % 26;
				n = n / 26;
				if(s == 0) {
					s = 26;
					n = n - 1;
				}
				namelist[j] = list[(int) (s-1)];
			}else {
				namelist[j] = list[(int) (n-1)];
			}
		}
		for(int k=exp-1;k>=0;k--) {
			name = name + namelist[k];
		}
		System.out.println(name);
	}

}