import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); StringBuilder sb = new StringBuilder(); long N = sc.nextLong(); int alp = (int) (N%26); N /= 26; str(alp,sb); while(N > 0){ N --; alp = (int) (N%26); N /= 26; str(alp,sb); } sb.reverse(); String ans = sb.toString(); System.out.println(ans); } public static void str(int alp,StringBuilder sb){ if(alp == 0){ sb.append("A"); }else if(alp == 1){ sb.append("B"); }else if(alp == 2){ sb.append("C"); }else if(alp == 3){ sb.append("D"); }else if(alp == 4){ sb.append("E"); }else if(alp == 5){ sb.append("F"); }else if(alp == 6){ sb.append("G"); }else if(alp == 7){ sb.append("H"); }else if(alp == 8){ sb.append("I"); }else if(alp == 9){ sb.append("J"); }else if(alp == 10){ sb.append("K"); }else if(alp == 11){ sb.append("L"); }else if(alp == 12){ sb.append("M"); }else if(alp == 13){ sb.append("N"); }else if(alp == 14){ sb.append("O"); }else if(alp == 15){ sb.append("P"); }else if(alp == 16){ sb.append("Q"); }else if(alp == 17){ sb.append("R"); }else if(alp == 18){ sb.append("C"); }else if(alp == 19){ sb.append("T"); }else if(alp == 20){ sb.append("U"); }else if(alp == 21){ sb.append("V"); }else if(alp == 22){ sb.append("W"); }else if(alp == 23){ sb.append("X"); }else if(alp == 24){ sb.append("Y"); }else if(alp == 25){ sb.append("Z"); } } }