Решение

fun maxNumberOfBalloons(text: String): Int {
    val counts = IntArray(26)
    for (char in text) counts[char - 'a']++

    return minOf(
        counts['b' - 'a'],
        counts['a' - 'a'],
        counts['l' - 'a'] / 2,
        counts['o' - 'a'] / 2,
        counts['n' - 'a']
    )
}