# 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;
        
    }
}