def isPalindrome(string):  
    left_pos = 0  
    right_pos = len(string) - 1  
      
    while right_pos >= left_pos:  
        if not string[left_pos] == string[right_pos]:  
            return False  
        left_pos += 1  
        right_pos -= 1  
    return True  
print(isPalindrome('aza'))   