number = input()
number = int(number)
group_num = input()
math_list = []
for i in range(number):
    math = input()
    math_list.append(math)
max_math = max(math_list)
max_math = int(max_math)
min_math = min(math_list)
min_math = int(min_math)
print(max_math - min_math)