import java.util.*;
public class Main {
	public static void main(String[] args) {
		Scanner scn = new Scanner(System.in);
		long n = scn.nextLong();
		fun(n);
	}
	public static void fun(long n) {
		if(n<27) {
			System.out.print((char)(n+96));
			return;
		}else if(n<703) {
			if(n%26!=0) {
			System.out.print((char)(n/26 + 96));
			System.out.print((char)(n%26 + 96));}
			else {
				System.out.print((char)(n/26 + 95));
				System.out.print((char)(26 + 96));
				return;
			}
		}else {
			if(n%26!=0) {
			fun(n/26);
			System.out.print((char)(n%26 + 96));}
			else {
				fun(n/26 - 1);
				System.out.print((char)(26 + 96));}
			return;
		}
	}
}	 import java.util.*; util.* java public class Main {
	public static void main(String[] args) {
		Scanner scn = new Scanner(System.in);
		long n = scn.nextLong();
		fun(n);
	}
	public static void fun(long n) {
		if(n<27) {
			System.out.print((char)(n+96));
			return;
		}else if(n<703) {
			if(n%26!=0) {
			System.out.print((char)(n/26 + 96));
			System.out.print((char)(n%26 + 96));}
			else {
				System.out.print((char)(n/26 + 95));
				System.out.print((char)(26 + 96));
				return;
			}
		}else {
			if(n%26!=0) {
			fun(n/26);
			System.out.print((char)(n%26 + 96));}
			else {
				fun(n/26 - 1);
				System.out.print((char)(26 + 96));}
			return;
		}
	}
} Main public static void main(String[] args) {
		Scanner scn = new Scanner(System.in);
		long n = scn.nextLong();
		fun(n);
	} main {
		Scanner scn = new Scanner(System.in);
		long n = scn.nextLong();
		fun(n);
	} Scanner scn = new Scanner(System.in); scn new Scanner(System.in) long n = scn.nextLong(); n scn.nextLong() scn.nextLong scn fun(n) fun n String[] args args public static void fun(long n) {
		if(n<27) {
			System.out.print((char)(n+96));
			return;
		}else if(n<703) {
			if(n%26!=0) {
			System.out.print((char)(n/26 + 96));
			System.out.print((char)(n%26 + 96));}
			else {
				System.out.print((char)(n/26 + 95));
				System.out.print((char)(26 + 96));
				return;
			}
		}else {
			if(n%26!=0) {
			fun(n/26);
			System.out.print((char)(n%26 + 96));}
			else {
				fun(n/26 - 1);
				System.out.print((char)(26 + 96));}
			return;
		}
	} fun {
		if(n<27) {
			System.out.print((char)(n+96));
			return;
		}else if(n<703) {
			if(n%26!=0) {
			System.out.print((char)(n/26 + 96));
			System.out.print((char)(n%26 + 96));}
			else {
				System.out.print((char)(n/26 + 95));
				System.out.print((char)(26 + 96));
				return;
			}
		}else {
			if(n%26!=0) {
			fun(n/26);
			System.out.print((char)(n%26 + 96));}
			else {
				fun(n/26 - 1);
				System.out.print((char)(26 + 96));}
			return;
		}
	} if(n<27) {
			System.out.print((char)(n+96));
			return;
		}else if(n<703) {
			if(n%26!=0) {
			System.out.print((char)(n/26 + 96));
			System.out.print((char)(n%26 + 96));}
			else {
				System.out.print((char)(n/26 + 95));
				System.out.print((char)(26 + 96));
				return;
			}
		}else {
			if(n%26!=0) {
			fun(n/26);
			System.out.print((char)(n%26 + 96));}
			else {
				fun(n/26 - 1);
				System.out.print((char)(26 + 96));}
			return;
		} n<27 n 27 {
			System.out.print((char)(n+96));
			return;
		} System.out.print((char)(n+96)) System.out.print System.out System System.out (char)(n+96) n 96 return; if(n<703) {
			if(n%26!=0) {
			System.out.print((char)(n/26 + 96));
			System.out.print((char)(n%26 + 96));}
			else {
				System.out.print((char)(n/26 + 95));
				System.out.print((char)(26 + 96));
				return;
			}
		}else {
			if(n%26!=0) {
			fun(n/26);
			System.out.print((char)(n%26 + 96));}
			else {
				fun(n/26 - 1);
				System.out.print((char)(26 + 96));}
			return;
		} n<703 n 703 {
			if(n%26!=0) {
			System.out.print((char)(n/26 + 96));
			System.out.print((char)(n%26 + 96));}
			else {
				System.out.print((char)(n/26 + 95));
				System.out.print((char)(26 + 96));
				return;
			}
		} if(n%26!=0) {
			System.out.print((char)(n/26 + 96));
			System.out.print((char)(n%26 + 96));}
			else {
				System.out.print((char)(n/26 + 95));
				System.out.print((char)(26 + 96));
				return;
			} n%26!=0 n%26 n 26 0 {
			System.out.print((char)(n/26 + 96));
			System.out.print((char)(n%26 + 96));} System.out.print((char)(n/26 + 96)) System.out.print System.out System System.out (char)(n/26 + 96) n/26 n 26 96 System.out.print((char)(n%26 + 96)) System.out.print System.out System System.out (char)(n%26 + 96) n%26 n 26 96 {
				System.out.print((char)(n/26 + 95));
				System.out.print((char)(26 + 96));
				return;
			} System.out.print((char)(n/26 + 95)) System.out.print System.out System System.out (char)(n/26 + 95) n/26 n 26 95 System.out.print((char)(26 + 96)) System.out.print System.out System System.out (char)(26 + 96) 26 96 return; {
			if(n%26!=0) {
			fun(n/26);
			System.out.print((char)(n%26 + 96));}
			else {
				fun(n/26 - 1);
				System.out.print((char)(26 + 96));}
			return;
		} if(n%26!=0) {
			fun(n/26);
			System.out.print((char)(n%26 + 96));}
			else {
				fun(n/26 - 1);
				System.out.print((char)(26 + 96));} n%26!=0 n%26 n 26 0 {
			fun(n/26);
			System.out.print((char)(n%26 + 96));} fun(n/26) fun n/26 n 26 System.out.print((char)(n%26 + 96)) System.out.print System.out System System.out (char)(n%26 + 96) n%26 n 26 96 {
				fun(n/26 - 1);
				System.out.print((char)(26 + 96));} fun(n/26 - 1) fun n/26 - 1 n/26 n 26 1 System.out.print((char)(26 + 96)) System.out.print System.out System System.out (char)(26 + 96) 26 96 return; long n n public class Main {
	public static void main(String[] args) {
		Scanner scn = new Scanner(System.in);
		long n = scn.nextLong();
		fun(n);
	}
	public static void fun(long n) {
		if(n<27) {
			System.out.print((char)(n+96));
			return;
		}else if(n<703) {
			if(n%26!=0) {
			System.out.print((char)(n/26 + 96));
			System.out.print((char)(n%26 + 96));}
			else {
				System.out.print((char)(n/26 + 95));
				System.out.print((char)(26 + 96));
				return;
			}
		}else {
			if(n%26!=0) {
			fun(n/26);
			System.out.print((char)(n%26 + 96));}
			else {
				fun(n/26 - 1);
				System.out.print((char)(26 + 96));}
			return;
		}
	}
} public class Main {
	public static void main(String[] args) {
		Scanner scn = new Scanner(System.in);
		long n = scn.nextLong();
		fun(n);
	}
	public static void fun(long n) {
		if(n<27) {
			System.out.print((char)(n+96));
			return;
		}else if(n<703) {
			if(n%26!=0) {
			System.out.print((char)(n/26 + 96));
			System.out.print((char)(n%26 + 96));}
			else {
				System.out.print((char)(n/26 + 95));
				System.out.print((char)(26 + 96));
				return;
			}
		}else {
			if(n%26!=0) {
			fun(n/26);
			System.out.print((char)(n%26 + 96));}
			else {
				fun(n/26 - 1);
				System.out.print((char)(26 + 96));}
			return;
		}
	}
} Main
import java.util.*;
public class Main {
	public static void main(String[] args) {
		Scanner scn = new Scanner(System.in);
		long n = scn.nextLong();
		fun(n);
	}
	public static void fun(long n) {
		if(n<27) {
			System.out.print((char)(n+96));
			return;
		}else if(n<703) {
			if(n%26!=0) {
			System.out.print((char)(n/26 + 96));
			System.out.print((char)(n%26 + 96));}
			else {
				System.out.print((char)(n/26 + 95));
				System.out.print((char)(26 + 96));
				return;
			}
		}else {
			if(n%26!=0) {
			fun(n/26);
			System.out.print((char)(n%26 + 96));}
			else {
				fun(n/26 - 1);
				System.out.print((char)(26 + 96));}
			return;
		}
	}
}	