function palindromeIndex(s) {
    let left = 0, right = s.length - 1
    while (left <= right) {
        if (s[left] !== s[right]) {
            if (isPalindrome(s.substring(left, right))) return right
            else if (isPalindrome(s.substring(left + 1, right + 1))) return left
            return -1
        } else {
            left++
            right--
        }
    }
    return -1
}

function isPalindrome(s) {
    for (let i = 0; i < Math.floor(s.length / 2); i++) {
        if (s[i] !== s[s.length - 1 - i]) return false
    }
    return true
}