string canPalindrome(string s){
    bool op1 = false;
        int slow = 1;
        int fast = s.length()-1;
        cout << s <<endl;
        while(fast > slow){
            if(s[fast] != s[slow]){
                op1 = true;
            }
            fast --;
            slow++;
        } 
        if(op1)return "second";
        else return "first";
}

int palindromeIndex(string s) {
    int idx = -1;
    int fast = s.length()-1;
    int slow = 0;
    
    while(slow < fast){
        if(s[slow] != s[fast]){
            string sub = s.substr(slow,(fast-slow)+1);
            string result = canPalindrome(sub);
            result == "first" ? idx=slow : idx = fast;
            return idx;
        }
        slow++;
        fast--;
    }
    return idx;
}