# 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()


if query_name in student_marks.keys():
    avg = float(sum(student_marks[query_name]) / len(student_marks[query_name]))
    print(f"{avg:.2f}")