# your code goes here
# your code goes here    
def isPalindrome(s: str) -> bool:
    temp = ""
    for i in s.lower():
        if "a" <= i <= "z" or "0" <= i <= "9" :
            temp = temp + i
    l,r = 0 , len(temp) -1
    while l<r:
        print(l,r,temp[l],temp[r])
        print(l,r,temp[l]!=temp[r])
        if temp[l] != temp[r]:
            return "false"
        r = r-1
        l = l+1
    return "true" 
 
print(isPalindrome("race a car"))

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