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.

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

Constraints
2 <= N <= 10
0 <= Marks <= 100

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

Sample Output
56.00