Just find the number of co-primes of 97 which are less than 97, as 97 itself is a prime all the numbers less than that are co-prime to it, had the question given as a group of order 96 then it would have been {1,3,5,7,11....}
Co-Primes:Two numbers are coprime if their highest common factor (or greatest common divisor if you must) is 1.