python longest consecutive sequence

1def longest(seq = input("""Please enter a series of random letters,
2i will guess the largest sequence of letters in order""").upper()):
3    
4    max_count = 0
5    max_char = ""
6    prev_char = ""
7    
8    for current in seq:
9        if prev_char == current:
10            count += 1
11        else:
12            count = 1
13        if count > max_count:
14            max_count = count
15            max_char = current
16        prev_char = current
17    print(max_char,max_count)
18
19longest()