TASK_07

def show_palindrome(value):
    result = ""
    limit = value
    limit /= 2
    limit = int(limit)
    for i in range(1, value+1):
        result += str(i)
    for i in range(value-1, 0, -1):
        result += str(i)
    return result


value = input()
value = int(value)
print(show_palindrome(value))