def long_repeat(line):

    substrings = []
    current_substring = ""
    for i, letter in enumerate(line):
        if i == 0:
            current_substring = letter
        else:
            if letter == current_substring[len(current_substring) - 1]:
                current_substring += letter
                if(i == len(line)- 1):
                    substrings.append(current_substring)
            else:
                substrings.append(current_substring)
                current_substring = letter

    lengths = []
    for substring in substrings:
        lengths.append(len(substring))

    if len(lengths) > 0:
        return  max(lengths)
    else:
        return 0

def get_length_of_longest_repeated_substring(text):
    """Outputs the length of the longest substring with the same letters.

    Args:
        text: Text in which to look for longest repeated substring.

    Returns:
        Length of the longest repeated character.
    """
    repeated_substrings = []
    current_substring = ''
    previous_character = ''

    for i, current_character in enumerate(text):
        if not current_substring:
            current_substring = current_character
            previous_character = current_character
            continue

        if current_character == previous_character:
            current_substring += letter
        else:
            repeated_substrings.append(current_substring)
            current_substring = letter

    if current_substring and len(current_substring) > 1:
        repeated_substrings.append(current_substring)

    max_length = 0
    for substring in repeated_substrings:
        if len(substring) > max_length:
            max_length = len(substring)

    return max_length

def get_length_of_longest_repeated_substring(string, n, i):
    i += 1
    while (i < n):
        current = string[i]
        previous = string[i - 1]
        if (current == previous):
            i += 1
        else:
            break
    return i - 1

def largestSubstring(string, n):
    length = 0
    i = 0
    while (i < n):
        end = get_length_of_longest_repeated_substring(string, n, i)
        length = max(end - i + 1, length)
        i = end + 1
    return length

#string = "aaaaa"

#n = len(string)

#print(largestSubstring(string, n))

>>> 5

#string = "sdsffffse"

#n = len(string)

#print(largestSubstring(string, n))

>>> 4