import java.util.*;
public class Main {
    public static long mod(long x, long y) {
    return x%y<0?x%y+(y<0?-y:y):x%y;
    } 
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long a = sc.nextLong()-1;
		StringBuilder sb = new StringBuilder();
        String str[] = {"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"};
        while(a>=0){int b = (int)mod(a,26);                   
                    sb.append(str[b]);
                    a=a/26-1;
                   }
		String ans = sb.toString();
        StringBuffer sf = new StringBuffer(ans);
		System.out.println(sf.reverse().toString());
	}
} import java.util.*; util.* java public class Main {
    public static long mod(long x, long y) {
    return x%y<0?x%y+(y<0?-y:y):x%y;
    } 
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long a = sc.nextLong()-1;
		StringBuilder sb = new StringBuilder();
        String str[] = {"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"};
        while(a>=0){int b = (int)mod(a,26);                   
                    sb.append(str[b]);
                    a=a/26-1;
                   }
		String ans = sb.toString();
        StringBuffer sf = new StringBuffer(ans);
		System.out.println(sf.reverse().toString());
	}
} Main public static long mod(long x, long y) {
    return x%y<0?x%y+(y<0?-y:y):x%y;
    } mod {
    return x%y<0?x%y+(y<0?-y:y):x%y;
    } return x%y<0?x%y+(y<0?-y:y):x%y; x%y<0?x%y+(y<0?-y:y):x%y x%y<0 x%y x y 0 x%y+(y<0?-y:y) x%y x y (y<0?-y:y) y<0 y 0 -y y y x%y x y long x x long y y public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long a = sc.nextLong()-1;
		StringBuilder sb = new StringBuilder();
        String str[] = {"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"};
        while(a>=0){int b = (int)mod(a,26);                   
                    sb.append(str[b]);
                    a=a/26-1;
                   }
		String ans = sb.toString();
        StringBuffer sf = new StringBuffer(ans);
		System.out.println(sf.reverse().toString());
	} main {
		Scanner sc = new Scanner(System.in);
		long a = sc.nextLong()-1;
		StringBuilder sb = new StringBuilder();
        String str[] = {"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"};
        while(a>=0){int b = (int)mod(a,26);                   
                    sb.append(str[b]);
                    a=a/26-1;
                   }
		String ans = sb.toString();
        StringBuffer sf = new StringBuffer(ans);
		System.out.println(sf.reverse().toString());
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long a = sc.nextLong()-1; a sc.nextLong()-1 sc.nextLong() sc.nextLong sc 1 StringBuilder sb = new StringBuilder(); sb new StringBuilder() String str[] = {"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"}; str {"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" while(a>=0){int b = (int)mod(a,26);                   
                    sb.append(str[b]);
                    a=a/26-1;
                   } a>=0 a 0 {int b = (int)mod(a,26);                   
                    sb.append(str[b]);
                    a=a/26-1;
                   } int b = (int)mod(a,26); b (int)mod(a,26) mod a 26 sb.append(str[b]) sb.append sb str[b] str b a=a/26-1 a a/26-1 a/26 a 26 1 String ans = sb.toString(); ans sb.toString() sb.toString sb StringBuffer sf = new StringBuffer(ans); sf new StringBuffer(ans) System.out.println(sf.reverse().toString()) System.out.println System.out System System.out sf.reverse().toString() sf.reverse().toString sf.reverse() sf.reverse sf String[] args args public class Main {
    public static long mod(long x, long y) {
    return x%y<0?x%y+(y<0?-y:y):x%y;
    } 
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long a = sc.nextLong()-1;
		StringBuilder sb = new StringBuilder();
        String str[] = {"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"};
        while(a>=0){int b = (int)mod(a,26);                   
                    sb.append(str[b]);
                    a=a/26-1;
                   }
		String ans = sb.toString();
        StringBuffer sf = new StringBuffer(ans);
		System.out.println(sf.reverse().toString());
	}
} public class Main {
    public static long mod(long x, long y) {
    return x%y<0?x%y+(y<0?-y:y):x%y;
    } 
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long a = sc.nextLong()-1;
		StringBuilder sb = new StringBuilder();
        String str[] = {"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"};
        while(a>=0){int b = (int)mod(a,26);                   
                    sb.append(str[b]);
                    a=a/26-1;
                   }
		String ans = sb.toString();
        StringBuffer sf = new StringBuffer(ans);
		System.out.println(sf.reverse().toString());
	}
} Main
import java.util.*;
public class Main {
    public static long mod(long x, long y) {
    return x%y<0?x%y+(y<0?-y:y):x%y;
    } 
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long a = sc.nextLong()-1;
		StringBuilder sb = new StringBuilder();
        String str[] = {"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"};
        while(a>=0){int b = (int)mod(a,26);                   
                    sb.append(str[b]);
                    a=a/26-1;
                   }
		String ans = sb.toString();
        StringBuffer sf = new StringBuffer(ans);
		System.out.println(sf.reverse().toString());
	}
}