function repeatedString(s: string, n: number): number {
    const sLen = s.length;
    // use regex to calculate the count of a's in s
    const aCount = (s.match(/a/g) || []).length;
    // how many times is the lenght of s in n
    const repCount = Math.trunc(n / sLen);
    // how many characters needs to be added so the repeated string's length matches n
    const remainder = n % sLen;
    // get a substring with a length equal to the remainder number
    const remainderSubstring = s.substring(0, remainder);
    // how many a's are present in the substring
    const aCountInSubstring =  (remainderSubstring.match(/a/g) || []).length;
    // result is the count of a's in the times needed to be repeated + the ones in the remainder substring
    return repCount * aCount + aCountInSubstring;
}