import java.util.*;
import java.io.*;
public class Main{
	public static void main(String[] args) throws Exception
	{
	  Scanner sc=new Scanner(System.in);
		Long n=sc.nextLong();
		List<Long> li=new ArrayList<Long>();
		Quadrillion(n);
		
		
	}
	public static void Quadrillion(Long n)
	{
		StringBuffer sb=new StringBuffer();
		while(n>0)
		{
			Long x=n%26;
			if(x==0)
			{
				sb.append('z');
				n=n/26-1;
			}
			else
			{
				sb.append((char)((x-1)+'a'));
				n=n/26;
			}
		}
		 System.out.println(sb.reverse());
	}

} import java.util.*; util.* java import java.io.*; io.* java public class Main{
	public static void main(String[] args) throws Exception
	{
	  Scanner sc=new Scanner(System.in);
		Long n=sc.nextLong();
		List<Long> li=new ArrayList<Long>();
		Quadrillion(n);
		
		
	}
	public static void Quadrillion(Long n)
	{
		StringBuffer sb=new StringBuffer();
		while(n>0)
		{
			Long x=n%26;
			if(x==0)
			{
				sb.append('z');
				n=n/26-1;
			}
			else
			{
				sb.append((char)((x-1)+'a'));
				n=n/26;
			}
		}
		 System.out.println(sb.reverse());
	}

} Main public static void main(String[] args) throws Exception
	{
	  Scanner sc=new Scanner(System.in);
		Long n=sc.nextLong();
		List<Long> li=new ArrayList<Long>();
		Quadrillion(n);
		
		
	} main {
	  Scanner sc=new Scanner(System.in);
		Long n=sc.nextLong();
		List<Long> li=new ArrayList<Long>();
		Quadrillion(n);
		
		
	} Scanner sc=new Scanner(System.in); sc new Scanner(System.in) Long n=sc.nextLong(); n sc.nextLong() sc.nextLong sc List<Long> li=new ArrayList<Long>(); li new ArrayList<Long>() Quadrillion(n) Quadrillion n String[] args args public static void Quadrillion(Long n)
	{
		StringBuffer sb=new StringBuffer();
		while(n>0)
		{
			Long x=n%26;
			if(x==0)
			{
				sb.append('z');
				n=n/26-1;
			}
			else
			{
				sb.append((char)((x-1)+'a'));
				n=n/26;
			}
		}
		 System.out.println(sb.reverse());
	} Quadrillion {
		StringBuffer sb=new StringBuffer();
		while(n>0)
		{
			Long x=n%26;
			if(x==0)
			{
				sb.append('z');
				n=n/26-1;
			}
			else
			{
				sb.append((char)((x-1)+'a'));
				n=n/26;
			}
		}
		 System.out.println(sb.reverse());
	} StringBuffer sb=new StringBuffer(); sb new StringBuffer() while(n>0)
		{
			Long x=n%26;
			if(x==0)
			{
				sb.append('z');
				n=n/26-1;
			}
			else
			{
				sb.append((char)((x-1)+'a'));
				n=n/26;
			}
		} n>0 n 0 {
			Long x=n%26;
			if(x==0)
			{
				sb.append('z');
				n=n/26-1;
			}
			else
			{
				sb.append((char)((x-1)+'a'));
				n=n/26;
			}
		} Long x=n%26; x n%26 n 26 if(x==0)
			{
				sb.append('z');
				n=n/26-1;
			}
			else
			{
				sb.append((char)((x-1)+'a'));
				n=n/26;
			} x==0 x 0 {
				sb.append('z');
				n=n/26-1;
			} sb.append('z') sb.append sb 'z' n=n/26-1 n n/26-1 n/26 n 26 1 {
				sb.append((char)((x-1)+'a'));
				n=n/26;
			} sb.append((char)((x-1)+'a')) sb.append sb (char)((x-1)+'a') (x-1) x 1 'a' n=n/26 n n/26 n 26 System.out.println(sb.reverse()) System.out.println System.out System System.out sb.reverse() sb.reverse sb Long n n public class Main{
	public static void main(String[] args) throws Exception
	{
	  Scanner sc=new Scanner(System.in);
		Long n=sc.nextLong();
		List<Long> li=new ArrayList<Long>();
		Quadrillion(n);
		
		
	}
	public static void Quadrillion(Long n)
	{
		StringBuffer sb=new StringBuffer();
		while(n>0)
		{
			Long x=n%26;
			if(x==0)
			{
				sb.append('z');
				n=n/26-1;
			}
			else
			{
				sb.append((char)((x-1)+'a'));
				n=n/26;
			}
		}
		 System.out.println(sb.reverse());
	}

} public class Main{
	public static void main(String[] args) throws Exception
	{
	  Scanner sc=new Scanner(System.in);
		Long n=sc.nextLong();
		List<Long> li=new ArrayList<Long>();
		Quadrillion(n);
		
		
	}
	public static void Quadrillion(Long n)
	{
		StringBuffer sb=new StringBuffer();
		while(n>0)
		{
			Long x=n%26;
			if(x==0)
			{
				sb.append('z');
				n=n/26-1;
			}
			else
			{
				sb.append((char)((x-1)+'a'));
				n=n/26;
			}
		}
		 System.out.println(sb.reverse());
	}

} Main
import java.util.*;
import java.io.*;
public class Main{
	public static void main(String[] args) throws Exception
	{
	  Scanner sc=new Scanner(System.in);
		Long n=sc.nextLong();
		List<Long> li=new ArrayList<Long>();
		Quadrillion(n);
		
		
	}
	public static void Quadrillion(Long n)
	{
		StringBuffer sb=new StringBuffer();
		while(n>0)
		{
			Long x=n%26;
			if(x==0)
			{
				sb.append('z');
				n=n/26-1;
			}
			else
			{
				sb.append((char)((x-1)+'a'));
				n=n/26;
			}
		}
		 System.out.println(sb.reverse());
	}

}
