import java.util.Scanner;

public class Main{

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner scn=new Scanner(System.in);
		long n=scn.nextLong();
	        System.out.println( res(n));

	}
	public static StringBuilder res(long n){
		if(n<=0){
			StringBuilder sb=new StringBuilder();
			return sb;
		}
		if(n<=26){
			StringBuilder sb=new StringBuilder();
			char ch = (char)((n-1)+'a');
			sb.append(ch);
			return sb;
		}
		  StringBuilder ans=new StringBuilder();
		  if(n%26==0){
		StringBuilder a= res(n/26-1);
		  ans.append(a);
		  }else{
			  StringBuilder a= res(n/26);
			  ans.append(a);
		  }
		  
		    long val=n%26;
		    if(val==0){
		    	val=26;
		    }
		    char ch=(char)((val-1)+'a');
		    ans.append(ch);
		    return ans;
		
	}

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

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner scn=new Scanner(System.in);
		long n=scn.nextLong();
	        System.out.println( res(n));

	}
	public static StringBuilder res(long n){
		if(n<=0){
			StringBuilder sb=new StringBuilder();
			return sb;
		}
		if(n<=26){
			StringBuilder sb=new StringBuilder();
			char ch = (char)((n-1)+'a');
			sb.append(ch);
			return sb;
		}
		  StringBuilder ans=new StringBuilder();
		  if(n%26==0){
		StringBuilder a= res(n/26-1);
		  ans.append(a);
		  }else{
			  StringBuilder a= res(n/26);
			  ans.append(a);
		  }
		  
		    long val=n%26;
		    if(val==0){
		    	val=26;
		    }
		    char ch=(char)((val-1)+'a');
		    ans.append(ch);
		    return ans;
		
	}

} Main public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner scn=new Scanner(System.in);
		long n=scn.nextLong();
	        System.out.println( res(n));

	} main {
		// TODO Auto-generated method stub
		Scanner scn=new Scanner(System.in);
		long n=scn.nextLong();
	        System.out.println( res(n));

	} Scanner scn=new Scanner(System.in); scn new Scanner(System.in) long n=scn.nextLong(); n scn.nextLong() scn.nextLong scn System.out.println( res(n)) System.out.println System.out System System.out res(n) res n String[] args args public static StringBuilder res(long n){
		if(n<=0){
			StringBuilder sb=new StringBuilder();
			return sb;
		}
		if(n<=26){
			StringBuilder sb=new StringBuilder();
			char ch = (char)((n-1)+'a');
			sb.append(ch);
			return sb;
		}
		  StringBuilder ans=new StringBuilder();
		  if(n%26==0){
		StringBuilder a= res(n/26-1);
		  ans.append(a);
		  }else{
			  StringBuilder a= res(n/26);
			  ans.append(a);
		  }
		  
		    long val=n%26;
		    if(val==0){
		    	val=26;
		    }
		    char ch=(char)((val-1)+'a');
		    ans.append(ch);
		    return ans;
		
	} res {
		if(n<=0){
			StringBuilder sb=new StringBuilder();
			return sb;
		}
		if(n<=26){
			StringBuilder sb=new StringBuilder();
			char ch = (char)((n-1)+'a');
			sb.append(ch);
			return sb;
		}
		  StringBuilder ans=new StringBuilder();
		  if(n%26==0){
		StringBuilder a= res(n/26-1);
		  ans.append(a);
		  }else{
			  StringBuilder a= res(n/26);
			  ans.append(a);
		  }
		  
		    long val=n%26;
		    if(val==0){
		    	val=26;
		    }
		    char ch=(char)((val-1)+'a');
		    ans.append(ch);
		    return ans;
		
	} if(n<=0){
			StringBuilder sb=new StringBuilder();
			return sb;
		} n<=0 n 0 {
			StringBuilder sb=new StringBuilder();
			return sb;
		} StringBuilder sb=new StringBuilder(); sb new StringBuilder() return sb; sb if(n<=26){
			StringBuilder sb=new StringBuilder();
			char ch = (char)((n-1)+'a');
			sb.append(ch);
			return sb;
		} n<=26 n 26 {
			StringBuilder sb=new StringBuilder();
			char ch = (char)((n-1)+'a');
			sb.append(ch);
			return sb;
		} StringBuilder sb=new StringBuilder(); sb new StringBuilder() char ch = (char)((n-1)+'a'); ch (char)((n-1)+'a') (n-1) n 1 'a' sb.append(ch) sb.append sb ch return sb; sb StringBuilder ans=new StringBuilder(); ans new StringBuilder() if(n%26==0){
		StringBuilder a= res(n/26-1);
		  ans.append(a);
		  }else{
			  StringBuilder a= res(n/26);
			  ans.append(a);
		  } n%26==0 n%26 n 26 0 {
		StringBuilder a= res(n/26-1);
		  ans.append(a);
		  } StringBuilder a= res(n/26-1); a res(n/26-1) res n/26-1 n/26 n 26 1 ans.append(a) ans.append ans a {
			  StringBuilder a= res(n/26);
			  ans.append(a);
		  } StringBuilder a= res(n/26); a res(n/26) res n/26 n 26 ans.append(a) ans.append ans a long val=n%26; val n%26 n 26 if(val==0){
		    	val=26;
		    } val==0 val 0 {
		    	val=26;
		    } val=26 val 26 char ch=(char)((val-1)+'a'); ch (char)((val-1)+'a') (val-1) val 1 'a' ans.append(ch) ans.append ans ch return ans; ans long n n public class Main{

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner scn=new Scanner(System.in);
		long n=scn.nextLong();
	        System.out.println( res(n));

	}
	public static StringBuilder res(long n){
		if(n<=0){
			StringBuilder sb=new StringBuilder();
			return sb;
		}
		if(n<=26){
			StringBuilder sb=new StringBuilder();
			char ch = (char)((n-1)+'a');
			sb.append(ch);
			return sb;
		}
		  StringBuilder ans=new StringBuilder();
		  if(n%26==0){
		StringBuilder a= res(n/26-1);
		  ans.append(a);
		  }else{
			  StringBuilder a= res(n/26);
			  ans.append(a);
		  }
		  
		    long val=n%26;
		    if(val==0){
		    	val=26;
		    }
		    char ch=(char)((val-1)+'a');
		    ans.append(ch);
		    return ans;
		
	}

} public class Main{

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner scn=new Scanner(System.in);
		long n=scn.nextLong();
	        System.out.println( res(n));

	}
	public static StringBuilder res(long n){
		if(n<=0){
			StringBuilder sb=new StringBuilder();
			return sb;
		}
		if(n<=26){
			StringBuilder sb=new StringBuilder();
			char ch = (char)((n-1)+'a');
			sb.append(ch);
			return sb;
		}
		  StringBuilder ans=new StringBuilder();
		  if(n%26==0){
		StringBuilder a= res(n/26-1);
		  ans.append(a);
		  }else{
			  StringBuilder a= res(n/26);
			  ans.append(a);
		  }
		  
		    long val=n%26;
		    if(val==0){
		    	val=26;
		    }
		    char ch=(char)((val-1)+'a');
		    ans.append(ch);
		    return ans;
		
	}

} Main
import java.util.Scanner;

public class Main{

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner scn=new Scanner(System.in);
		long n=scn.nextLong();
	        System.out.println( res(n));

	}
	public static StringBuilder res(long n){
		if(n<=0){
			StringBuilder sb=new StringBuilder();
			return sb;
		}
		if(n<=26){
			StringBuilder sb=new StringBuilder();
			char ch = (char)((n-1)+'a');
			sb.append(ch);
			return sb;
		}
		  StringBuilder ans=new StringBuilder();
		  if(n%26==0){
		StringBuilder a= res(n/26-1);
		  ans.append(a);
		  }else{
			  StringBuilder a= res(n/26);
			  ans.append(a);
		  }
		  
		    long val=n%26;
		    if(val==0){
		    	val=26;
		    }
		    char ch=(char)((val-1)+'a');
		    ans.append(ch);
		    return ans;
		
	}

}