import java.util.Scanner;


	public class Main {
		
		

		public static void main(String[] args) {

			Scanner sc = new Scanner(System.in);
	        
			long n = sc.nextLong();
			 
	        String ret = "";
	        
	        while(n>0) {
	        	int c = (int)(n%26L);
	        	if(c==0) {
	        		c=26;
	        	}
	        	n = (n-c)/26L;
	        	ret = (char)('a'+c-1) + ret;
	        }
	        
	        System.out.println(ret);
		}
	} 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 ret = "";
	        
	        while(n>0) {
	        	int c = (int)(n%26L);
	        	if(c==0) {
	        		c=26;
	        	}
	        	n = (n-c)/26L;
	        	ret = (char)('a'+c-1) + ret;
	        }
	        
	        System.out.println(ret);
		}
	} Main public static void main(String[] args) {

			Scanner sc = new Scanner(System.in);
	        
			long n = sc.nextLong();
			 
	        String ret = "";
	        
	        while(n>0) {
	        	int c = (int)(n%26L);
	        	if(c==0) {
	        		c=26;
	        	}
	        	n = (n-c)/26L;
	        	ret = (char)('a'+c-1) + ret;
	        }
	        
	        System.out.println(ret);
		} main {

			Scanner sc = new Scanner(System.in);
	        
			long n = sc.nextLong();
			 
	        String ret = "";
	        
	        while(n>0) {
	        	int c = (int)(n%26L);
	        	if(c==0) {
	        		c=26;
	        	}
	        	n = (n-c)/26L;
	        	ret = (char)('a'+c-1) + ret;
	        }
	        
	        System.out.println(ret);
		} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc String ret = ""; ret "" while(n>0) {
	        	int c = (int)(n%26L);
	        	if(c==0) {
	        		c=26;
	        	}
	        	n = (n-c)/26L;
	        	ret = (char)('a'+c-1) + ret;
	        } n>0 n 0 {
	        	int c = (int)(n%26L);
	        	if(c==0) {
	        		c=26;
	        	}
	        	n = (n-c)/26L;
	        	ret = (char)('a'+c-1) + ret;
	        } int c = (int)(n%26L); c (int)(n%26L) n 26L if(c==0) {
	        		c=26;
	        	} c==0 c 0 {
	        		c=26;
	        	} c=26 c 26 n = (n-c)/26L n (n-c)/26L (n-c) n c 26L ret = (char)('a'+c-1) + ret ret (char)('a'+c-1) + ret (char)('a'+c-1) 'a'+c 'a' c 1 ret System.out.println(ret) System.out.println System.out System System.out ret String[] args args public class Main {
		
		

		public static void main(String[] args) {

			Scanner sc = new Scanner(System.in);
	        
			long n = sc.nextLong();
			 
	        String ret = "";
	        
	        while(n>0) {
	        	int c = (int)(n%26L);
	        	if(c==0) {
	        		c=26;
	        	}
	        	n = (n-c)/26L;
	        	ret = (char)('a'+c-1) + ret;
	        }
	        
	        System.out.println(ret);
		}
	} public class Main {
		
		

		public static void main(String[] args) {

			Scanner sc = new Scanner(System.in);
	        
			long n = sc.nextLong();
			 
	        String ret = "";
	        
	        while(n>0) {
	        	int c = (int)(n%26L);
	        	if(c==0) {
	        		c=26;
	        	}
	        	n = (n-c)/26L;
	        	ret = (char)('a'+c-1) + ret;
	        }
	        
	        System.out.println(ret);
		}
	} 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 ret = "";
	        
	        while(n>0) {
	        	int c = (int)(n%26L);
	        	if(c==0) {
	        		c=26;
	        	}
	        	n = (n-c)/26L;
	        	ret = (char)('a'+c-1) + ret;
	        }
	        
	        System.out.println(ret);
		}
	}
