import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		long N = sc.nextLong();
		int aPos = ('a');
		StringBuilder res = new StringBuilder();
		while (N != 0) {
			if (N % 26 == 0) {
				res.insert(0, 'z');
				N--;
			} else {
				res.insert(0, (char) (aPos + (N % 26) - 1));
			}
			N /= 26;
		}
		System.out.println(res);
	}
}
/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