find_percentage_by_name.py

'''
problem--
You have a record of N students. Each record contains the student's name, and their percent marks in Maths, Physics and Chemistry. The marks can be floating values. The user enters some integer N followed by the names and marks for N students. You are required to save the record in a dictionary data type. The user then enters a student's name. Output the average percentage marks obtained by that student, correct to two decimal places.

Input Format--
The first line contains the integer N, the number of students. The next N lines contains the name and marks obtained by that student separated by a space. The final line contains the name of a particular student previously listed.

Constraints--
2 <= N <= 10
0 <= marks <= 100

Output Format--
Print one line: The average of the marks obtained by the particular student correct to 2 decimal places.

Sample Input 0

3
Krishna 67 68 69
Arjun 70 98 63
Malika 52 56 60
Malika

Sample Output 0

56.00
'''

#code is here

N=int(input())
d={}
for _ in range(N):
    name,*marks=input().split()
    marks=list(map(float,marks))
    d[name]=marks
q=input()
t=sum(d[q])/3
print("{:.2f}".format(t))