public static long repeatedString(string s, long n)
    {
        long aNum = s.Count(a => a == 'a');
        long repeats = n / s.Length;
        int leftOver = (int)(n % s.Length);
        
        aNum = aNum * repeats;
        aNum += s[..leftOver].Count(a => a == 'a');
        
        return aNum;
    }