#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char* convertToTitle(int n) {
    if (n <= 0) {
        return "-1";
    }

    char* result = (char*)malloc(sizeof(char) * 10); // Max 7 chars for 10^6, plus null terminator
    if (result == NULL) {
        return NULL; // Handle memory allocation failure
    }
    int i = 0;

    while (n > 0) {
        n--; // Adjust to 0-based indexing for modulo operation
        result[i++] = (char)('A' + (n % 26));
        n /= 26;
    }
    result[i] = '\0';

 
    int start = 0;
    int end = i - 1;
    while (start < end) {
        char temp = result[start];
        result[start] = result[end];
        result[end] = temp;
        start++;
        end--;
    }
    return result;
}

int main() {
    int n;

    if (scanf("%d", &n) != 1) {
        printf("Invalid Input\n");
        return 1;
    }

    char* title = convertToTitle(n);
    if (title != NULL) {
        printf("%s\n", title);
        if (strcmp(title, "-1") != 0) {
            free(title);
        }
    } else {
        printf("Memory allocation failed\n");
    }

    return 0;
}