import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long input = scanner.nextLong();

        StringBuilder sbr = new StringBuilder();
        while ( input > 0 ){
            input -= 1;
            sbr.append( (char) ( 'a' + input % 26 ));
            input /= 26;
        }

        System.out.println( sbr.reverse().toString());
    }
}
/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