import java.util.*; 
import java.io.*;

public class Main {
    static StringTokenizer st;
    static BufferedReader br;  
    static PrintWriter out;
 
    public static void main(String[] args) throws IOException {
        br = new BufferedReader(new InputStreamReader(System.in));

        long N = nextLong();
    
        int[] level = new int[100];

        int x = 0;
        while(N > 0){
            int temp = (int) (N % 26);
            if(temp==0){
                level[x] = 26;
                N = N/26-1;
            }
            else{
                level[x] = temp;
                N = N/26;
            }

            x++;
        }
       
        String ans = "";
        char alphabet[] = "abcdefghijklmnopqrstuvwxyz".toCharArray();
        for(int i = x-1; i>=0; i--){
            ans += alphabet[level[i]-1]; //0 base
        }

        System.out.println(ans);

        
    }
    
      
    public static int nextInt() throws IOException {
        return Integer.parseInt(next());
    }
    public static long nextLong() throws IOException {
        return Long.parseLong(next());
    }

    public static double nextDouble() throws IOException {
        return Double.parseDouble(next());
    }

    static String next() throws IOException {
        while (st == null || !st.hasMoreTokens())
            st = new StringTokenizer(br.readLine().trim());
        return st.nextToken();
    }
} import java.util.*; util.* java import java.io.*; io.* java public class Main {
    static StringTokenizer st;
    static BufferedReader br;  
    static PrintWriter out;
 
    public static void main(String[] args) throws IOException {
        br = new BufferedReader(new InputStreamReader(System.in));

        long N = nextLong();
    
        int[] level = new int[100];

        int x = 0;
        while(N > 0){
            int temp = (int) (N % 26);
            if(temp==0){
                level[x] = 26;
                N = N/26-1;
            }
            else{
                level[x] = temp;
                N = N/26;
            }

            x++;
        }
       
        String ans = "";
        char alphabet[] = "abcdefghijklmnopqrstuvwxyz".toCharArray();
        for(int i = x-1; i>=0; i--){
            ans += alphabet[level[i]-1]; //0 base
        }

        System.out.println(ans);

        
    }
    
      
    public static int nextInt() throws IOException {
        return Integer.parseInt(next());
    }
    public static long nextLong() throws IOException {
        return Long.parseLong(next());
    }

    public static double nextDouble() throws IOException {
        return Double.parseDouble(next());
    }

    static String next() throws IOException {
        while (st == null || !st.hasMoreTokens())
            st = new StringTokenizer(br.readLine().trim());
        return st.nextToken();
    }
} Main static StringTokenizer st; st static BufferedReader br; br static PrintWriter out; out public static void main(String[] args) throws IOException {
        br = new BufferedReader(new InputStreamReader(System.in));

        long N = nextLong();
    
        int[] level = new int[100];

        int x = 0;
        while(N > 0){
            int temp = (int) (N % 26);
            if(temp==0){
                level[x] = 26;
                N = N/26-1;
            }
            else{
                level[x] = temp;
                N = N/26;
            }

            x++;
        }
       
        String ans = "";
        char alphabet[] = "abcdefghijklmnopqrstuvwxyz".toCharArray();
        for(int i = x-1; i>=0; i--){
            ans += alphabet[level[i]-1]; //0 base
        }

        System.out.println(ans);

        
    } main {
        br = new BufferedReader(new InputStreamReader(System.in));

        long N = nextLong();
    
        int[] level = new int[100];

        int x = 0;
        while(N > 0){
            int temp = (int) (N % 26);
            if(temp==0){
                level[x] = 26;
                N = N/26-1;
            }
            else{
                level[x] = temp;
                N = N/26;
            }

            x++;
        }
       
        String ans = "";
        char alphabet[] = "abcdefghijklmnopqrstuvwxyz".toCharArray();
        for(int i = x-1; i>=0; i--){
            ans += alphabet[level[i]-1]; //0 base
        }

        System.out.println(ans);

        
    } br = new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) long N = nextLong(); N nextLong() nextLong int[] level = new int[100]; level new int[100] 100 int x = 0; x 0 while(N > 0){
            int temp = (int) (N % 26);
            if(temp==0){
                level[x] = 26;
                N = N/26-1;
            }
            else{
                level[x] = temp;
                N = N/26;
            }

            x++;
        } N > 0 N 0 {
            int temp = (int) (N % 26);
            if(temp==0){
                level[x] = 26;
                N = N/26-1;
            }
            else{
                level[x] = temp;
                N = N/26;
            }

            x++;
        } int temp = (int) (N % 26); temp (int) (N % 26) N 26 if(temp==0){
                level[x] = 26;
                N = N/26-1;
            }
            else{
                level[x] = temp;
                N = N/26;
            } temp==0 temp 0 {
                level[x] = 26;
                N = N/26-1;
            } level[x] = 26 level[x] level x 26 N = N/26-1 N N/26-1 N/26 N 26 1 {
                level[x] = temp;
                N = N/26;
            } level[x] = temp level[x] level x temp N = N/26 N N/26 N 26 x++ x String ans = ""; ans "" char alphabet[] = "abcdefghijklmnopqrstuvwxyz".toCharArray(); alphabet "abcdefghijklmnopqrstuvwxyz".toCharArray() "abcdefghijklmnopqrstuvwxyz".toCharArray "abcdefghijklmnopqrstuvwxyz" for(int i = x-1; i>=0; i--){
            ans += alphabet[level[i]-1]; //0 base
        } int i = x-1; int i = x-1; i x-1 x 1 i>=0 i 0 i-- i-- i {
            ans += alphabet[level[i]-1]; //0 base
        } {
            ans += alphabet[level[i]-1]; //0 base
        } ans += alphabet[level[i]-1] ans alphabet[level[i]-1] alphabet level[i]-1 level[i] level i 1 System.out.println(ans) System.out.println System.out System System.out ans String[] args args public static int nextInt() throws IOException {
        return Integer.parseInt(next());
    } nextInt {
        return Integer.parseInt(next());
    } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next public static long nextLong() throws IOException {
        return Long.parseLong(next());
    } nextLong {
        return Long.parseLong(next());
    } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next public static double nextDouble() throws IOException {
        return Double.parseDouble(next());
    } nextDouble {
        return Double.parseDouble(next());
    } return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next static String next() throws IOException {
        while (st == null || !st.hasMoreTokens())
            st = new StringTokenizer(br.readLine().trim());
        return st.nextToken();
    } next {
        while (st == null || !st.hasMoreTokens())
            st = new StringTokenizer(br.readLine().trim());
        return st.nextToken();
    } while (st == null || !st.hasMoreTokens())
            st = new StringTokenizer(br.readLine().trim()); st == null || !st.hasMoreTokens() st == null st null !st.hasMoreTokens() st.hasMoreTokens() st.hasMoreTokens st st = new StringTokenizer(br.readLine().trim()) st new StringTokenizer(br.readLine().trim()) return st.nextToken(); st.nextToken() st.nextToken st public class Main {
    static StringTokenizer st;
    static BufferedReader br;  
    static PrintWriter out;
 
    public static void main(String[] args) throws IOException {
        br = new BufferedReader(new InputStreamReader(System.in));

        long N = nextLong();
    
        int[] level = new int[100];

        int x = 0;
        while(N > 0){
            int temp = (int) (N % 26);
            if(temp==0){
                level[x] = 26;
                N = N/26-1;
            }
            else{
                level[x] = temp;
                N = N/26;
            }

            x++;
        }
       
        String ans = "";
        char alphabet[] = "abcdefghijklmnopqrstuvwxyz".toCharArray();
        for(int i = x-1; i>=0; i--){
            ans += alphabet[level[i]-1]; //0 base
        }

        System.out.println(ans);

        
    }
    
      
    public static int nextInt() throws IOException {
        return Integer.parseInt(next());
    }
    public static long nextLong() throws IOException {
        return Long.parseLong(next());
    }

    public static double nextDouble() throws IOException {
        return Double.parseDouble(next());
    }

    static String next() throws IOException {
        while (st == null || !st.hasMoreTokens())
            st = new StringTokenizer(br.readLine().trim());
        return st.nextToken();
    }
} public class Main {
    static StringTokenizer st;
    static BufferedReader br;  
    static PrintWriter out;
 
    public static void main(String[] args) throws IOException {
        br = new BufferedReader(new InputStreamReader(System.in));

        long N = nextLong();
    
        int[] level = new int[100];

        int x = 0;
        while(N > 0){
            int temp = (int) (N % 26);
            if(temp==0){
                level[x] = 26;
                N = N/26-1;
            }
            else{
                level[x] = temp;
                N = N/26;
            }

            x++;
        }
       
        String ans = "";
        char alphabet[] = "abcdefghijklmnopqrstuvwxyz".toCharArray();
        for(int i = x-1; i>=0; i--){
            ans += alphabet[level[i]-1]; //0 base
        }

        System.out.println(ans);

        
    }
    
      
    public static int nextInt() throws IOException {
        return Integer.parseInt(next());
    }
    public static long nextLong() throws IOException {
        return Long.parseLong(next());
    }

    public static double nextDouble() throws IOException {
        return Double.parseDouble(next());
    }

    static String next() throws IOException {
        while (st == null || !st.hasMoreTokens())
            st = new StringTokenizer(br.readLine().trim());
        return st.nextToken();
    }
} Main
import java.util.*; 
import java.io.*;

public class Main {
    static StringTokenizer st;
    static BufferedReader br;  
    static PrintWriter out;
 
    public static void main(String[] args) throws IOException {
        br = new BufferedReader(new InputStreamReader(System.in));

        long N = nextLong();
    
        int[] level = new int[100];

        int x = 0;
        while(N > 0){
            int temp = (int) (N % 26);
            if(temp==0){
                level[x] = 26;
                N = N/26-1;
            }
            else{
                level[x] = temp;
                N = N/26;
            }

            x++;
        }
       
        String ans = "";
        char alphabet[] = "abcdefghijklmnopqrstuvwxyz".toCharArray();
        for(int i = x-1; i>=0; i--){
            ans += alphabet[level[i]-1]; //0 base
        }

        System.out.println(ans);

        
    }
    
      
    public static int nextInt() throws IOException {
        return Integer.parseInt(next());
    }
    public static long nextLong() throws IOException {
        return Long.parseLong(next());
    }

    public static double nextDouble() throws IOException {
        return Double.parseDouble(next());
    }

    static String next() throws IOException {
        while (st == null || !st.hasMoreTokens())
            st = new StringTokenizer(br.readLine().trim());
        return st.nextToken();
    }
}