import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
      	String s="";
      for(int i=0;i<15;i++){
        if(n==0){break;}
      	long a =n%26;
      	s=s+alphabet(a);
      	if(a!=0)n=n/26;
        else{n=n/26-1;}
      }
      StringBuffer buf = new StringBuffer(s);
      String ans = buf.reverse().toString();
      System.out.println(ans);
    }
  
  public static String alphabet(long i){
  	if(i==1){return("a");}
    if(i==2){return("b");}
    if(i==3){return("c");}
    if(i==4){return("d");}
    if(i==5){return("e");}
    if(i==6){return("f");}
    if(i==7){return("g");}
    if(i==8){return("h");}
    if(i==9){return("i");}
    if(i==10){return("j");}
    if(i==11){return("k");}
    if(i==12){return("l");}
    if(i==13){return("m");}
    if(i==14){return("n");}
    if(i==15){return("o");}
    if(i==16){return("p");}
    if(i==17){return("q");}
    if(i==18){return("r");}
    if(i==19){return("s");}
    if(i==20){return("t");}
    if(i==21){return("u");}
    if(i==22){return("v");}
    if(i==23){return("w");}
    if(i==24){return("x");}
    if(i==25){return("y");}
    if(i==0){return("z");}
    return("");
  }
  
} import java.util.*; util.* java public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
      	String s="";
      for(int i=0;i<15;i++){
        if(n==0){break;}
      	long a =n%26;
      	s=s+alphabet(a);
      	if(a!=0)n=n/26;
        else{n=n/26-1;}
      }
      StringBuffer buf = new StringBuffer(s);
      String ans = buf.reverse().toString();
      System.out.println(ans);
    }
  
  public static String alphabet(long i){
  	if(i==1){return("a");}
    if(i==2){return("b");}
    if(i==3){return("c");}
    if(i==4){return("d");}
    if(i==5){return("e");}
    if(i==6){return("f");}
    if(i==7){return("g");}
    if(i==8){return("h");}
    if(i==9){return("i");}
    if(i==10){return("j");}
    if(i==11){return("k");}
    if(i==12){return("l");}
    if(i==13){return("m");}
    if(i==14){return("n");}
    if(i==15){return("o");}
    if(i==16){return("p");}
    if(i==17){return("q");}
    if(i==18){return("r");}
    if(i==19){return("s");}
    if(i==20){return("t");}
    if(i==21){return("u");}
    if(i==22){return("v");}
    if(i==23){return("w");}
    if(i==24){return("x");}
    if(i==25){return("y");}
    if(i==0){return("z");}
    return("");
  }
  
} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
      	String s="";
      for(int i=0;i<15;i++){
        if(n==0){break;}
      	long a =n%26;
      	s=s+alphabet(a);
      	if(a!=0)n=n/26;
        else{n=n/26-1;}
      }
      StringBuffer buf = new StringBuffer(s);
      String ans = buf.reverse().toString();
      System.out.println(ans);
    } main {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
      	String s="";
      for(int i=0;i<15;i++){
        if(n==0){break;}
      	long a =n%26;
      	s=s+alphabet(a);
      	if(a!=0)n=n/26;
        else{n=n/26-1;}
      }
      StringBuffer buf = new StringBuffer(s);
      String ans = buf.reverse().toString();
      System.out.println(ans);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc String s=""; s "" for(int i=0;i<15;i++){
        if(n==0){break;}
      	long a =n%26;
      	s=s+alphabet(a);
      	if(a!=0)n=n/26;
        else{n=n/26-1;}
      } int i=0; int i=0; i 0 i<15 i 15 i++ i++ i {
        if(n==0){break;}
      	long a =n%26;
      	s=s+alphabet(a);
      	if(a!=0)n=n/26;
        else{n=n/26-1;}
      } {
        if(n==0){break;}
      	long a =n%26;
      	s=s+alphabet(a);
      	if(a!=0)n=n/26;
        else{n=n/26-1;}
      } if(n==0){break;} n==0 n 0 {break;} break; long a =n%26; a n%26 n 26 s=s+alphabet(a) s s+alphabet(a) s alphabet(a) alphabet a if(a!=0)n=n/26;
        else{n=n/26-1;} a!=0 a 0 n=n/26 n n/26 n 26 {n=n/26-1;} n=n/26-1 n n/26-1 n/26 n 26 1 StringBuffer buf = new StringBuffer(s); buf new StringBuffer(s) String ans = buf.reverse().toString(); ans buf.reverse().toString() buf.reverse().toString buf.reverse() buf.reverse buf System.out.println(ans) System.out.println System.out System System.out ans String[] args args public static String alphabet(long i){
  	if(i==1){return("a");}
    if(i==2){return("b");}
    if(i==3){return("c");}
    if(i==4){return("d");}
    if(i==5){return("e");}
    if(i==6){return("f");}
    if(i==7){return("g");}
    if(i==8){return("h");}
    if(i==9){return("i");}
    if(i==10){return("j");}
    if(i==11){return("k");}
    if(i==12){return("l");}
    if(i==13){return("m");}
    if(i==14){return("n");}
    if(i==15){return("o");}
    if(i==16){return("p");}
    if(i==17){return("q");}
    if(i==18){return("r");}
    if(i==19){return("s");}
    if(i==20){return("t");}
    if(i==21){return("u");}
    if(i==22){return("v");}
    if(i==23){return("w");}
    if(i==24){return("x");}
    if(i==25){return("y");}
    if(i==0){return("z");}
    return("");
  } alphabet {
  	if(i==1){return("a");}
    if(i==2){return("b");}
    if(i==3){return("c");}
    if(i==4){return("d");}
    if(i==5){return("e");}
    if(i==6){return("f");}
    if(i==7){return("g");}
    if(i==8){return("h");}
    if(i==9){return("i");}
    if(i==10){return("j");}
    if(i==11){return("k");}
    if(i==12){return("l");}
    if(i==13){return("m");}
    if(i==14){return("n");}
    if(i==15){return("o");}
    if(i==16){return("p");}
    if(i==17){return("q");}
    if(i==18){return("r");}
    if(i==19){return("s");}
    if(i==20){return("t");}
    if(i==21){return("u");}
    if(i==22){return("v");}
    if(i==23){return("w");}
    if(i==24){return("x");}
    if(i==25){return("y");}
    if(i==0){return("z");}
    return("");
  } if(i==1){return("a");} i==1 i 1 {return("a");} return("a"); ("a") if(i==2){return("b");} i==2 i 2 {return("b");} return("b"); ("b") if(i==3){return("c");} i==3 i 3 {return("c");} return("c"); ("c") if(i==4){return("d");} i==4 i 4 {return("d");} return("d"); ("d") if(i==5){return("e");} i==5 i 5 {return("e");} return("e"); ("e") if(i==6){return("f");} i==6 i 6 {return("f");} return("f"); ("f") if(i==7){return("g");} i==7 i 7 {return("g");} return("g"); ("g") if(i==8){return("h");} i==8 i 8 {return("h");} return("h"); ("h") if(i==9){return("i");} i==9 i 9 {return("i");} return("i"); ("i") if(i==10){return("j");} i==10 i 10 {return("j");} return("j"); ("j") if(i==11){return("k");} i==11 i 11 {return("k");} return("k"); ("k") if(i==12){return("l");} i==12 i 12 {return("l");} return("l"); ("l") if(i==13){return("m");} i==13 i 13 {return("m");} return("m"); ("m") if(i==14){return("n");} i==14 i 14 {return("n");} return("n"); ("n") if(i==15){return("o");} i==15 i 15 {return("o");} return("o"); ("o") if(i==16){return("p");} i==16 i 16 {return("p");} return("p"); ("p") if(i==17){return("q");} i==17 i 17 {return("q");} return("q"); ("q") if(i==18){return("r");} i==18 i 18 {return("r");} return("r"); ("r") if(i==19){return("s");} i==19 i 19 {return("s");} return("s"); ("s") if(i==20){return("t");} i==20 i 20 {return("t");} return("t"); ("t") if(i==21){return("u");} i==21 i 21 {return("u");} return("u"); ("u") if(i==22){return("v");} i==22 i 22 {return("v");} return("v"); ("v") if(i==23){return("w");} i==23 i 23 {return("w");} return("w"); ("w") if(i==24){return("x");} i==24 i 24 {return("x");} return("x"); ("x") if(i==25){return("y");} i==25 i 25 {return("y");} return("y"); ("y") if(i==0){return("z");} i==0 i 0 {return("z");} return("z"); ("z") return(""); ("") long i i public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
      	String s="";
      for(int i=0;i<15;i++){
        if(n==0){break;}
      	long a =n%26;
      	s=s+alphabet(a);
      	if(a!=0)n=n/26;
        else{n=n/26-1;}
      }
      StringBuffer buf = new StringBuffer(s);
      String ans = buf.reverse().toString();
      System.out.println(ans);
    }
  
  public static String alphabet(long i){
  	if(i==1){return("a");}
    if(i==2){return("b");}
    if(i==3){return("c");}
    if(i==4){return("d");}
    if(i==5){return("e");}
    if(i==6){return("f");}
    if(i==7){return("g");}
    if(i==8){return("h");}
    if(i==9){return("i");}
    if(i==10){return("j");}
    if(i==11){return("k");}
    if(i==12){return("l");}
    if(i==13){return("m");}
    if(i==14){return("n");}
    if(i==15){return("o");}
    if(i==16){return("p");}
    if(i==17){return("q");}
    if(i==18){return("r");}
    if(i==19){return("s");}
    if(i==20){return("t");}
    if(i==21){return("u");}
    if(i==22){return("v");}
    if(i==23){return("w");}
    if(i==24){return("x");}
    if(i==25){return("y");}
    if(i==0){return("z");}
    return("");
  }
  
} public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
      	String s="";
      for(int i=0;i<15;i++){
        if(n==0){break;}
      	long a =n%26;
      	s=s+alphabet(a);
      	if(a!=0)n=n/26;
        else{n=n/26-1;}
      }
      StringBuffer buf = new StringBuffer(s);
      String ans = buf.reverse().toString();
      System.out.println(ans);
    }
  
  public static String alphabet(long i){
  	if(i==1){return("a");}
    if(i==2){return("b");}
    if(i==3){return("c");}
    if(i==4){return("d");}
    if(i==5){return("e");}
    if(i==6){return("f");}
    if(i==7){return("g");}
    if(i==8){return("h");}
    if(i==9){return("i");}
    if(i==10){return("j");}
    if(i==11){return("k");}
    if(i==12){return("l");}
    if(i==13){return("m");}
    if(i==14){return("n");}
    if(i==15){return("o");}
    if(i==16){return("p");}
    if(i==17){return("q");}
    if(i==18){return("r");}
    if(i==19){return("s");}
    if(i==20){return("t");}
    if(i==21){return("u");}
    if(i==22){return("v");}
    if(i==23){return("w");}
    if(i==24){return("x");}
    if(i==25){return("y");}
    if(i==0){return("z");}
    return("");
  }
  
} Main
import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
      	String s="";
      for(int i=0;i<15;i++){
        if(n==0){break;}
      	long a =n%26;
      	s=s+alphabet(a);
      	if(a!=0)n=n/26;
        else{n=n/26-1;}
      }
      StringBuffer buf = new StringBuffer(s);
      String ans = buf.reverse().toString();
      System.out.println(ans);
    }
  
  public static String alphabet(long i){
  	if(i==1){return("a");}
    if(i==2){return("b");}
    if(i==3){return("c");}
    if(i==4){return("d");}
    if(i==5){return("e");}
    if(i==6){return("f");}
    if(i==7){return("g");}
    if(i==8){return("h");}
    if(i==9){return("i");}
    if(i==10){return("j");}
    if(i==11){return("k");}
    if(i==12){return("l");}
    if(i==13){return("m");}
    if(i==14){return("n");}
    if(i==15){return("o");}
    if(i==16){return("p");}
    if(i==17){return("q");}
    if(i==18){return("r");}
    if(i==19){return("s");}
    if(i==20){return("t");}
    if(i==21){return("u");}
    if(i==22){return("v");}
    if(i==23){return("w");}
    if(i==24){return("x");}
    if(i==25){return("y");}
    if(i==0){return("z");}
    return("");
  }
  
}