if name == 'main': n = int(input()) student_marks = {} for _ in range(n): name, *line = input().split() scores = list(map(float, line)) student_marks[name] = scores query_name = input()

First we do Sum Of the marks And Then Take Len of marks

sum_of_marks = sum(student_marks[query_name]) length_of_query = len(student_marks[query_name])

Divide marks with numbers of marks(numbers of marks means how many subjects of marks)

average_marks = sum_of_marks / length_of_query

add decimal point

formated = format(average_marks,".2f")

print(formated)