Input Format
The first line contains the integer , the number of students. The next  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
Output Format
Print one line: The average of the marks obtained by the particular student correct to 2 decimal places.

### Problem solution in python 2 programming language.

d={}
for i in range(int(raw_input())):
line=raw_input().split()
d[line]=sum(map(float,line[1:]))/3

print '%.2f' % d[raw_input()]

### Problem solution in python 3 programming language.

d={}
for i in range(int(input())):
line= input().split()
d[line]=sum(map(float,line[1:]))/3

print '%.2f' % d[input()]

#### Second solution

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:
x = ((float(student_marks[query_name]) +
float(student_marks[query_name]) +
float(student_marks[query_name])) / 3)
print('%.2f' % x)