import java.util.Scanner;
public class Main{
    public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    long N = sc.nextLong();
    String S = "";
    String A[] = {"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(N>26){
      long tmp = (N-1L)%26;
      // if(tmp==-1L){
      //   tmp = 25L;
      // }
      S+=A[(int)tmp];
      N = (N -1L) /26L ;
      // System.out.println(N);
    }
    long tmp2 = N-1L;
    // if(tmp2==-1L){
    //   tmp2 = 25L;
    // }
    S+=A[(int)tmp2];
    StringBuffer str = new StringBuffer(S);
    String S2 = str.reverse().toString();
    System.out.println(S2);

  }
}

// 1000000000000001
// 9223372036854775807 import java.util.Scanner; Scanner java.util public class Main{
    public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    long N = sc.nextLong();
    String S = "";
    String A[] = {"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(N>26){
      long tmp = (N-1L)%26;
      // if(tmp==-1L){
      //   tmp = 25L;
      // }
      S+=A[(int)tmp];
      N = (N -1L) /26L ;
      // System.out.println(N);
    }
    long tmp2 = N-1L;
    // if(tmp2==-1L){
    //   tmp2 = 25L;
    // }
    S+=A[(int)tmp2];
    StringBuffer str = new StringBuffer(S);
    String S2 = str.reverse().toString();
    System.out.println(S2);

  }
} Main public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    long N = sc.nextLong();
    String S = "";
    String A[] = {"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(N>26){
      long tmp = (N-1L)%26;
      // if(tmp==-1L){
      //   tmp = 25L;
      // }
      S+=A[(int)tmp];
      N = (N -1L) /26L ;
      // System.out.println(N);
    }
    long tmp2 = N-1L;
    // if(tmp2==-1L){
    //   tmp2 = 25L;
    // }
    S+=A[(int)tmp2];
    StringBuffer str = new StringBuffer(S);
    String S2 = str.reverse().toString();
    System.out.println(S2);

  } main {
    Scanner sc = new Scanner(System.in);
    long N = sc.nextLong();
    String S = "";
    String A[] = {"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(N>26){
      long tmp = (N-1L)%26;
      // if(tmp==-1L){
      //   tmp = 25L;
      // }
      S+=A[(int)tmp];
      N = (N -1L) /26L ;
      // System.out.println(N);
    }
    long tmp2 = N-1L;
    // if(tmp2==-1L){
    //   tmp2 = 25L;
    // }
    S+=A[(int)tmp2];
    StringBuffer str = new StringBuffer(S);
    String S2 = str.reverse().toString();
    System.out.println(S2);

  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long N = sc.nextLong(); N sc.nextLong() sc.nextLong sc String S = ""; S "" String A[] = {"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 {"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(N>26){
      long tmp = (N-1L)%26;
      // if(tmp==-1L){
      //   tmp = 25L;
      // }
      S+=A[(int)tmp];
      N = (N -1L) /26L ;
      // System.out.println(N);
    } N>26 N 26 {
      long tmp = (N-1L)%26;
      // if(tmp==-1L){
      //   tmp = 25L;
      // }
      S+=A[(int)tmp];
      N = (N -1L) /26L ;
      // System.out.println(N);
    } long tmp = (N-1L)%26; tmp (N-1L)%26 (N-1L) N 1L 26 S+=A[(int)tmp] S A[(int)tmp] A (int)tmp N = (N -1L) /26L N (N -1L) /26L (N -1L) N 1L 26L long tmp2 = N-1L; tmp2 N-1L N 1L S+=A[(int)tmp2] S A[(int)tmp2] A (int)tmp2 StringBuffer str = new StringBuffer(S); str new StringBuffer(S) String S2 = str.reverse().toString(); S2 str.reverse().toString() str.reverse().toString str.reverse() str.reverse str System.out.println(S2) System.out.println System.out System System.out S2 String[] args args public class Main{
    public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    long N = sc.nextLong();
    String S = "";
    String A[] = {"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(N>26){
      long tmp = (N-1L)%26;
      // if(tmp==-1L){
      //   tmp = 25L;
      // }
      S+=A[(int)tmp];
      N = (N -1L) /26L ;
      // System.out.println(N);
    }
    long tmp2 = N-1L;
    // if(tmp2==-1L){
    //   tmp2 = 25L;
    // }
    S+=A[(int)tmp2];
    StringBuffer str = new StringBuffer(S);
    String S2 = str.reverse().toString();
    System.out.println(S2);

  }
} public class Main{
    public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    long N = sc.nextLong();
    String S = "";
    String A[] = {"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(N>26){
      long tmp = (N-1L)%26;
      // if(tmp==-1L){
      //   tmp = 25L;
      // }
      S+=A[(int)tmp];
      N = (N -1L) /26L ;
      // System.out.println(N);
    }
    long tmp2 = N-1L;
    // if(tmp2==-1L){
    //   tmp2 = 25L;
    // }
    S+=A[(int)tmp2];
    StringBuffer str = new StringBuffer(S);
    String S2 = str.reverse().toString();
    System.out.println(S2);

  }
} Main
import java.util.Scanner;
public class Main{
    public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    long N = sc.nextLong();
    String S = "";
    String A[] = {"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(N>26){
      long tmp = (N-1L)%26;
      // if(tmp==-1L){
      //   tmp = 25L;
      // }
      S+=A[(int)tmp];
      N = (N -1L) /26L ;
      // System.out.println(N);
    }
    long tmp2 = N-1L;
    // if(tmp2==-1L){
    //   tmp2 = 25L;
    // }
    S+=A[(int)tmp2];
    StringBuffer str = new StringBuffer(S);
    String S2 = str.reverse().toString();
    System.out.println(S2);

  }
}

// 1000000000000001
// 9223372036854775807