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

void convertToTitle(long long int n)
{
    char result[100];
    int index = 0;
    
    if(n<=0)
    {
        printf("Invalid input");
        return;
    }
    while(n>0)
    {
        n--;
        int remainder = n % 26;
        result[index++] = 'A'+remainder;
        n\=26;
    }
    for (int i = index - 1; i>=0; i--)
    {
        printf("%c",result[i]);
    }
    printf("\n");
}

int main()
{
    long long int n;
    if(scanf("%lld",&n)!=1)
    {
        printf("Invalid input\n";
        return 0;)
    }
    convertToTitle(n);
    return 0;
}