trello.py

def find(h, string_so_far):
    if len(string_so_far) == 9:
        return string_so_far[::-1]
    for j, char in enumerate(letters):
        if (h - j) % 37 == 0:
            h = (h-j)/37
            string_so_far += letters[j]
            return find(h, string_so_far)
        
print find(956446786872726, '')