def count_n(file):
    """
    amount of N
    """
    f = open(file, 'r')
    text = f.read()
    text = text.replace('\r', '')
    text = text.replace('\n', '')
    f.close()
    l = len(text)
    n = text.count('N')
    print('total length =', l)
    print('#N =', n)
    print("it's", round(n / l * 100, 3), '%')


def count_repeatitions(file):
    """
    повторы длины >= 1000
    """
    f = open(file, 'r')
    text = f.read()
    text = text.replace('\r', '')
    text = text.replace('\n', '')
    f.close()
    ans = 0
    l_curr = 0
    for ch in text:
        if ch != 'N':
            if l_curr >= 1000:
                ans += 1
            l_curr = 0
        else:
            l_curr += 1
    if l_curr >= 1000:
        ans += 1
    print('amount of repetitions with len >= 1000 is', ans)


file = 'sequence.fasta'
count_n(file)
count_repeatitions(file)