import java.util.*;
  
public class Main{
    public static void main(final String[] args){
       
        final Scanner sc = new Scanner(System.in);

        String abc = "abcdefghijklmnopqrstuvwxyz";
        Long alf = 26l;
        Long N = sc.nextLong();
        String ans = "";

        for(;N>0;){
            Long Num = N-1;
            int tStr = (int)(Num%alf);
            ans = abc.substring(tStr,tStr+1)+ans;
            N =  Num/alf;
        }
        System.out.println(ans);
    }
} import java.util.*; util.* java public class Main{
    public static void main(final String[] args){
       
        final Scanner sc = new Scanner(System.in);

        String abc = "abcdefghijklmnopqrstuvwxyz";
        Long alf = 26l;
        Long N = sc.nextLong();
        String ans = "";

        for(;N>0;){
            Long Num = N-1;
            int tStr = (int)(Num%alf);
            ans = abc.substring(tStr,tStr+1)+ans;
            N =  Num/alf;
        }
        System.out.println(ans);
    }
} Main public static void main(final String[] args){
       
        final Scanner sc = new Scanner(System.in);

        String abc = "abcdefghijklmnopqrstuvwxyz";
        Long alf = 26l;
        Long N = sc.nextLong();
        String ans = "";

        for(;N>0;){
            Long Num = N-1;
            int tStr = (int)(Num%alf);
            ans = abc.substring(tStr,tStr+1)+ans;
            N =  Num/alf;
        }
        System.out.println(ans);
    } main {
       
        final Scanner sc = new Scanner(System.in);

        String abc = "abcdefghijklmnopqrstuvwxyz";
        Long alf = 26l;
        Long N = sc.nextLong();
        String ans = "";

        for(;N>0;){
            Long Num = N-1;
            int tStr = (int)(Num%alf);
            ans = abc.substring(tStr,tStr+1)+ans;
            N =  Num/alf;
        }
        System.out.println(ans);
    } final Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String abc = "abcdefghijklmnopqrstuvwxyz"; abc "abcdefghijklmnopqrstuvwxyz" Long alf = 26l; alf 26l Long N = sc.nextLong(); N sc.nextLong() sc.nextLong sc String ans = ""; ans "" for(;N>0;){
            Long Num = N-1;
            int tStr = (int)(Num%alf);
            ans = abc.substring(tStr,tStr+1)+ans;
            N =  Num/alf;
        } ; N>0 N 0 {
            Long Num = N-1;
            int tStr = (int)(Num%alf);
            ans = abc.substring(tStr,tStr+1)+ans;
            N =  Num/alf;
        } {
            Long Num = N-1;
            int tStr = (int)(Num%alf);
            ans = abc.substring(tStr,tStr+1)+ans;
            N =  Num/alf;
        } Long Num = N-1; Num N-1 N 1 int tStr = (int)(Num%alf); tStr (int)(Num%alf) Num alf ans = abc.substring(tStr,tStr+1)+ans ans abc.substring(tStr,tStr+1)+ans abc.substring(tStr,tStr+1) abc.substring abc tStr tStr+1 tStr 1 ans N =  Num/alf N Num/alf Num alf System.out.println(ans) System.out.println System.out System System.out ans final String[] args args public class Main{
    public static void main(final String[] args){
       
        final Scanner sc = new Scanner(System.in);

        String abc = "abcdefghijklmnopqrstuvwxyz";
        Long alf = 26l;
        Long N = sc.nextLong();
        String ans = "";

        for(;N>0;){
            Long Num = N-1;
            int tStr = (int)(Num%alf);
            ans = abc.substring(tStr,tStr+1)+ans;
            N =  Num/alf;
        }
        System.out.println(ans);
    }
} public class Main{
    public static void main(final String[] args){
       
        final Scanner sc = new Scanner(System.in);

        String abc = "abcdefghijklmnopqrstuvwxyz";
        Long alf = 26l;
        Long N = sc.nextLong();
        String ans = "";

        for(;N>0;){
            Long Num = N-1;
            int tStr = (int)(Num%alf);
            ans = abc.substring(tStr,tStr+1)+ans;
            N =  Num/alf;
        }
        System.out.println(ans);
    }
} Main
import java.util.*;
  
public class Main{
    public static void main(final String[] args){
       
        final Scanner sc = new Scanner(System.in);

        String abc = "abcdefghijklmnopqrstuvwxyz";
        Long alf = 26l;
        Long N = sc.nextLong();
        String ans = "";

        for(;N>0;){
            Long Num = N-1;
            int tStr = (int)(Num%alf);
            ans = abc.substring(tStr,tStr+1)+ans;
            N =  Num/alf;
        }
        System.out.println(ans);
    }
}