import java.util.*;

public class Main{
	
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
  	long n=sc.nextLong(),m=n;
    StringBuffer sb=new StringBuffer();
    
    
    while(n>0){
      long f=n%26;
      
      if(f==0){
        sb.append('z');
        n=n/26-1;
      }else{
        long i=1;
        for(char al='a';al<='z';al++){
          if(f==i){
            sb.append(al);
          }
          i++;
        }
        n=n/26;
      }
      
    }
    sb.reverse();
    System.out.println(sb);
  }
} import java.util.*; util.* java public class Main{
	
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
  	long n=sc.nextLong(),m=n;
    StringBuffer sb=new StringBuffer();
    
    
    while(n>0){
      long f=n%26;
      
      if(f==0){
        sb.append('z');
        n=n/26-1;
      }else{
        long i=1;
        for(char al='a';al<='z';al++){
          if(f==i){
            sb.append(al);
          }
          i++;
        }
        n=n/26;
      }
      
    }
    sb.reverse();
    System.out.println(sb);
  }
} Main public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
  	long n=sc.nextLong(),m=n;
    StringBuffer sb=new StringBuffer();
    
    
    while(n>0){
      long f=n%26;
      
      if(f==0){
        sb.append('z');
        n=n/26-1;
      }else{
        long i=1;
        for(char al='a';al<='z';al++){
          if(f==i){
            sb.append(al);
          }
          i++;
        }
        n=n/26;
      }
      
    }
    sb.reverse();
    System.out.println(sb);
  } main {
    Scanner sc = new Scanner(System.in);
  	long n=sc.nextLong(),m=n;
    StringBuffer sb=new StringBuffer();
    
    
    while(n>0){
      long f=n%26;
      
      if(f==0){
        sb.append('z');
        n=n/26-1;
      }else{
        long i=1;
        for(char al='a';al<='z';al++){
          if(f==i){
            sb.append(al);
          }
          i++;
        }
        n=n/26;
      }
      
    }
    sb.reverse();
    System.out.println(sb);
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n=sc.nextLong() n sc.nextLong() sc.nextLong sc m=n; m n StringBuffer sb=new StringBuffer(); sb new StringBuffer() while(n>0){
      long f=n%26;
      
      if(f==0){
        sb.append('z');
        n=n/26-1;
      }else{
        long i=1;
        for(char al='a';al<='z';al++){
          if(f==i){
            sb.append(al);
          }
          i++;
        }
        n=n/26;
      }
      
    } n>0 n 0 {
      long f=n%26;
      
      if(f==0){
        sb.append('z');
        n=n/26-1;
      }else{
        long i=1;
        for(char al='a';al<='z';al++){
          if(f==i){
            sb.append(al);
          }
          i++;
        }
        n=n/26;
      }
      
    } long f=n%26; f n%26 n 26 if(f==0){
        sb.append('z');
        n=n/26-1;
      }else{
        long i=1;
        for(char al='a';al<='z';al++){
          if(f==i){
            sb.append(al);
          }
          i++;
        }
        n=n/26;
      } f==0 f 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 {
        long i=1;
        for(char al='a';al<='z';al++){
          if(f==i){
            sb.append(al);
          }
          i++;
        }
        n=n/26;
      } long i=1; i 1 for(char al='a';al<='z';al++){
          if(f==i){
            sb.append(al);
          }
          i++;
        } char al='a'; char al='a'; al 'a' al<='z' al 'z' al++ al++ al {
          if(f==i){
            sb.append(al);
          }
          i++;
        } {
          if(f==i){
            sb.append(al);
          }
          i++;
        } if(f==i){
            sb.append(al);
          } f==i f i {
            sb.append(al);
          } sb.append(al) sb.append sb al i++ i n=n/26 n n/26 n 26 sb.reverse() sb.reverse sb System.out.println(sb) System.out.println System.out System System.out sb String[] args args public class Main{
	
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
  	long n=sc.nextLong(),m=n;
    StringBuffer sb=new StringBuffer();
    
    
    while(n>0){
      long f=n%26;
      
      if(f==0){
        sb.append('z');
        n=n/26-1;
      }else{
        long i=1;
        for(char al='a';al<='z';al++){
          if(f==i){
            sb.append(al);
          }
          i++;
        }
        n=n/26;
      }
      
    }
    sb.reverse();
    System.out.println(sb);
  }
} public class Main{
	
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
  	long n=sc.nextLong(),m=n;
    StringBuffer sb=new StringBuffer();
    
    
    while(n>0){
      long f=n%26;
      
      if(f==0){
        sb.append('z');
        n=n/26-1;
      }else{
        long i=1;
        for(char al='a';al<='z';al++){
          if(f==i){
            sb.append(al);
          }
          i++;
        }
        n=n/26;
      }
      
    }
    sb.reverse();
    System.out.println(sb);
  }
} Main
import java.util.*;

public class Main{
	
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
  	long n=sc.nextLong(),m=n;
    StringBuffer sb=new StringBuffer();
    
    
    while(n>0){
      long f=n%26;
      
      if(f==0){
        sb.append('z');
        n=n/26-1;
      }else{
        long i=1;
        for(char al='a';al<='z';al++){
          if(f==i){
            sb.append(al);
          }
          i++;
        }
        n=n/26;
      }
      
    }
    sb.reverse();
    System.out.println(sb);
  }
}
