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);
  }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz